contracts/*: golint updates for this or self warning

* node: close AccountsManager in new Close method

* p2p/simulations, p2p/simulations/adapters: handle node close on shutdown

* node: move node ephemeralKeystore cleanup to stop method

* node: call Stop in Node.Close method

* cmd/geth: close node.Node created with makeFullNode in cli commands

* node: close Node instances in tests

* cmd/geth, node: minor code style fixes

* cmd, console, miner, mobile: proper node Close() termination

cmd/puppeth: handle pre-set Petersburg number, save changed fork rules

* docs: add audit reports

* docs: better filenames

* Named functions and defined a basic EIP191 content type list

* Written basic content type functions

* Added ecRecover method in the clef api

* Updated the extapi changelog and addded indications in the README

* Changed the version of the external API

* Added tests for 0x45

* Implementing UnmarshalJSON() for TypedData

* Working on TypedData

* Solved the auditlog issue

* Changed method to signTypedData

* Changed mimes and implemented the 'encodeType' function for EIP-712

* Polished docstrings, ran goimports and swapped fmt.Errorf with errors.New where possible

* Drafted recursive encodeData

* Ran goimports and gofmt

* Drafted first version of EIP-712, including tests

* Temporarily switched to using common.Address in tests

* Drafted text/validator and and rewritten []byte as hexutil.Bytes

* Solved stringified address encoding issue

* Changed the property type required by signData from bytes to interface{}

* Fixed bugs in 'data/typed' signs

* Brought legal warning back after temporarily disabling it for development

* Added example RPC calls for account_signData and account_signTypedData

* Named functions and defined a basic EIP191 content type list

* Written basic content type functions

* Added ecRecover method in the clef api

* Updated the extapi changelog and addded indications in the README

* Added tests for 0x45

* Implementing UnmarshalJSON() for TypedData

* Working on TypedData

* Solved the auditlog issue

* Changed method to signTypedData

* Changed mimes and implemented the 'encodeType' function for EIP-712

* Polished docstrings, ran goimports and swapped fmt.Errorf with errors.New where possible

* Drafted recursive encodeData

* Ran goimports and gofmt

* Drafted first version of EIP-712, including tests

* Temporarily switched to using common.Address in tests

* Drafted text/validator and and rewritten []byte as hexutil.Bytes

* Solved stringified address encoding issue

* Changed the property type required by signData from bytes to interface{}

* Fixed bugs in 'data/typed' signs

* Brought legal warning back after temporarily disabling it for development

* Added example RPC calls for account_signData and account_signTypedData

* Polished and fixed PR

* Polished and fixed PR

* Solved malformed data panics and also wrote tests

* Solved malformed data panics and also wrote tests

* Added alphabetical sorting to type dependencies

* Added alphabetical sorting to type dependencies

* Added pretty print to data/typed UI

* Added pretty print to data/typed UI

* signer: more tests for typed data

* signer: more tests for typed data

* Fixed TestMalformedData4 errors and renamed IsValid to Validate

* Fixed TestMalformedData4 errors and renamed IsValid to Validate

* Fixed more new failing tests and deanonymised some functions

* Fixed more new failing tests and deanonymised some functions

* Added types to EIP712 output in cliui

* Added types to EIP712 output in cliui

* Fixed regexp issues

* Fixed regexp issues

* Added pseudo-failing test

* Added pseudo-failing test

* Fixed false positive test

* Fixed false positive test

* Added PrettyPrint method

* Added PrettyPrint method

* signer: refactor formatting and UI

* signer: make ui use new message format for signing

* Fixed breaking changes

* Fixed rules_test failing test

* Added extra regexp for reference types

* signer: more hard types

* Fixed failing test, formatted files

* signer: use golang/x keccak

* Fixed goimports error

* clef, signer: address some review concerns

* Implemented latest recommendations

* Fixed comments and uintint256 issue

* accounts, signer: fix mimetypes, add interface to sign data with passphrase

* signer, accounts: remove duplicated code, pass hash preimages to signing

* signer: prevent panic in type assertions, make cliui print rawdata as quotable-safe

* signer: linter fixes, remove deprecated crypto dependency

* accounts: fix goimport

Fixes #16286

* accounts, eth, clique: implement external backend + move sighash calc to backend

* signer: implement account_Version on external API

* accounts/external: enable ipc, add copyright

* accounts, internal, signer: formatting

* node: go fmt

* flags: disallow --dev in combo with --externalsigner

* accounts: remove clique-specific signing method, replace with more generic

* accounts, consensus: formatting + fix error in tests

* signer/core: remove (test-) import cycle

* clique: remove unused import

* accounts: remove CliqueHash and avoid dependency on package crypto

* consensus/clique: unduplicate header encoding

cmd, core, params: add support for Goerli

New APIs added:

    client.RegisterName(namespace, service) // makes service available to server
    client.Notify(ctx, method, args...)     // sends a notification
    ClientFromContext(ctx)                  // to get a client in handler method

This is essentially a rewrite of the server-side code. JSON-RPC
processing code is now the same on both server and client side. Many
minor issues were fixed in the process and there is a new test suite for
JSON-RPC spec compliance (and non-compliance in some cases).

List of behavior changes:

- Method handlers are now called with a per-request context instead of a
  per-connection context. The context is canceled right after the method
  returns.
- Subscription error channels are always closed when the connection
  ends. There is no need to also wait on the Notifier's Closed channel
  to detect whether the subscription has ended.
- Client now omits "params" instead of sending "params": null when there
  are no arguments to a call. The previous behavior was not compliant
  with the spec. The server still accepts "params": null.
- Floating point numbers are allowed as "id". The spec doesn't allow
  them, but we handle request "id" as json.RawMessage and guarantee that
  the same number will be sent back.
- Logging is improved significantly. There is now a message at DEBUG
  level for each RPC call served.

This change clears up confusion around the two ways in which nodes
can be added to the table.

When a neighbors packet is received as a reply to findnode, the nodes
contained in the reply are added as 'seen' entries if sufficient space
is available.

When a ping is received and the endpoint verification has taken place,
the remote node is added as a 'verified' entry or moved to the front of
the bucket if present. This also updates the node's IP address and port
if they have changed.

* cmd, eth: Added in the flag to step geth once sync based on input

* cmd, eth: 16400 Add an option to stop geth once in sync.

* cmd: 16400 Add an option to stop geth once in sync. WIP

* cmd/geth/main, les/fletcher: added in light mode support

* cmd/geth/main, les/fletcher: Cleaned Comments and code for light mode

* cmd: 16400 Fixed formatting issue and cleaned code

* cmd, eth, les: 16400 Fixed formatting issues

* cmd, eth, les: Performed gofmt to update formatting

* cmd, eth, les: Fixed bugs resulting formatting

* cmd/geth, eth/, les: switched to downloader event

* eth: Fixed styling and gen_config

* eth/: Fix nil error in config file

* cmd/geth: Updated countdown log

* les/fetcher.go: Removed depcreated channel

* eth/downloader.go: Removed deprecated select

* cmd/geth, cmd/utils: Fixed minor issues

* eth: Reverted config files to proper format

* eth: Fixed typo in config file

* cmd/geth, eth/down: Updated code to use header time stamp

* eth/downloader: Changed the time threshold to 10 minutes

* cmd/geth, eth/downloader: Updated downloading event to pass latest header

* cmd/geth: Updated main to use right timer object

* cmd/geth: Removed unused failed event

* cmd/geth: added in correct time field with type assertion

* cmd/geth, cmd/utils: Updated flag to use boolean

* cmd/geth, cmd/utils, eth/downloader: Cleaned up code based on recommendations

* cmd/geth: Removed unneeded import

* cmd/geth, eth/downloader: fixed event field and suggested changes

* cmd/geth, cmd/utils: Updated flag and linting issue

This change resolves multiple issues around handling of endpoint proofs.
The proof is now done separately for each IP and completing the proof
requires a matching ping hash.

Also remove waitping because it's equivalent to sleep. waitping was
slightly more efficient, but that may cause issues with findnode if
packets are reordered and the remote end sees findnode before pong.

Logging of received packets was hitherto done after handling the packet,
which meant that sent replies were logged before the packet that
generated them. This change splits up packet handling into 'preverify'
and 'handle'. The error from 'preverify' is logged, but 'handle' happens
after the message is logged. This fixes the order. Packet logs now
contain the node ID.