* signer: introduce external signer command

* cmd/signer, rpc: Implement new signer. Add info about remote user to Context

* signer: refactored request/response, made use of urfave.cli

* cmd/signer: Use common flags

* cmd/signer: methods to validate calldata against abi

* cmd/signer: work on abi parser

* signer: add mutex around UI

* cmd/signer: add json 4byte directory, remove passwords from api

* cmd/signer: minor changes

* cmd/signer: Use ErrRequestDenied, enable lightkdf

* cmd/signer: implement tests

* cmd/signer: made possible for UI to modify tx parameters

* cmd/signer: refactors, removed channels in ui comms, added UI-api via stdin/out

* cmd/signer: Made lowercase json-definitions, added UI-signer test functionality

* cmd/signer: update documentation

* cmd/signer: fix bugs, improve abi detection, abi argument display

* cmd/signer: minor change in json format

* cmd/signer: rework json communication

* cmd/signer: implement mixcase addresses in API, fix json id bug

* cmd/signer: rename fromaccount, update pythonpoc with new json encoding format

* cmd/signer: make use of new abi interface

* signer: documentation

* signer/main: remove redundant  option

* signer: implement audit logging

* signer: create package 'signer', minor changes

* common: add 0x-prefix to mixcaseaddress in json marshalling + validation

* signer, rules, storage: implement rules + ephemeral storage for signer rules

* signer: implement OnApprovedTx, change signing response (API BREAKAGE)

* signer: refactoring + documentation

* signer/rules: implement dispatching to next handler

* signer: docs

* signer/rules: hide json-conversion from users, ensure context is cleaned

* signer: docs

* signer: implement validation rules, change signature of call_info

* signer: fix log flaw with string pointer

* signer: implement custom 4byte databsae that saves submitted signatures

* signer/storage: implement aes-gcm-backed credential storage

* accounts: implement json unmarshalling of url

* signer: fix listresponse, fix gas->uint64

* node: make http/ipc start methods public

* signer: add ipc capability+review concerns

* accounts: correct docstring

* signer: address review concerns

* rpc: go fmt -s

* signer: review concerns+ baptize Clef

* signer,node: move Start-functions to separate file

* signer: formatting

core: txpool stable underprice drop order, perf fixes

core/state: fix ripemd-cornercase in Copy

core/state: fix bug in copy of copy State

travis, appveyor: bump to Go 1.10.1

This commit is meant to allow ecosystem projects such as ethersphere
to minimize CI build times by specifying an environment variable with
the packages to run tests on.

If the environment variable isn't defined the build script will test
all packages so this shouldn't affect the main go-ethereum repository.

The 'from' and 'to' methods on StateTransitions are reader methods and
shouldn't have inadvertent side effects on state.

It is safe to remove the check in 'from' because account existence is
implicitly checked by the nonce and balance checks. If the account has
non-zero balance or nonce, it must exist. Even if the sender account has
nonce zero at the start of the state transition or no balance, the nonce
is incremented before execution and the account will be created at that
time.

It is safe to remove the check in 'to' because the EVM creates the
account if necessary.

Fixes #15119

Dockerfile.alltools: fix invalid command

* common: delete StringToAddress, StringToHash

These functions are confusing because they don't parse hex, but use the
bytes of the string. This change removes them, replacing all uses of
StringToAddress(s) by BytesToAddress([]byte(s)).

* eth/filters: remove incorrect use of common.BytesToAddress

cmd/puppeth: fix node deploys for updated dockerfile user

Change handling of dirty objects in state

Most of these methods did not contain all the relevant information
inside the object and were not using a similar formatting type.
Moreover, the existence of a suboptimal String method breaks usage
with more advanced data dumping tools like go-spew.