Original change by @jpeletier 

* core: fix import errors on clique crashes + empty blocks

* cosensus/clique, core: add test for the mirrored state issue

* core: address todo question wrt log count

* core: raise a louder warning for non-clique known blocks

* consensus,core,miner: avoid overhead of creating a new block

* consensus: nitpick dot

* consensus: fix some comment formatting nits

* all: simplify timestamps to uint64

* tests: update definitions

* clef, faucet, mobile: leftover uint64 fixups

* ethash: fix tests

* graphql: update schema for timestamp

* ethash: remove unused variable

* 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

* 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

This is an attempt to fix the flaky consensus/ethash tests under macOS.

* consensus, miner: stale block supporting

* consensus, miner: refactor seal signature

* cmd, consensus, eth: add miner noverify flag

* cmd, consensus, miner: polish

* miner: commit state which is relative with sealing result

* consensus, core, miner, mobile: introduce sealHash interface

* miner: evict pending task with threshold

* miner: go fmt

* consensus/ethash: start remote ggoroutine to handle remote mining

* consensus/ethash: expose remote miner api

* consensus/ethash: expose submitHashrate api

* miner, ethash: push empty block to sealer without waiting execution

* consensus, internal: add getHashrate API for ethash

* consensus: add three method for consensus interface

* miner: expose consensus engine running status to miner

* eth, miner: specify etherbase when miner created

* miner: commit new work when consensus engine is started

* consensus, miner: fix some logics

* all: delete useless interfaces

* consensus: polish a bit

* keystore, ethash, eth, miner, rpc, whisperv6: tech debt with now defunct set.

* whisperv5: swap out gopkg.in/fatih/set.v0 with supported set

correct the algorithm in the comments for fakeBlockNumber， from "min" to "max".

"proot-of-work" to "proof-of-work"

Use Read instead of Sum to avoid internal allocations and
copying the state.

name                      old time/op  new time/op  delta
CacheGeneration-8          764ms ± 1%   579ms ± 1%  -24.22%  (p=0.000 n=20+17)
SmallDatasetGeneration-8  75.2ms ±12%  60.6ms ±10%  -19.37%  (p=0.000 n=20+20)
HashimotoLight-8          1.58ms ±11%  1.55ms ± 8%     ~     (p=0.322 n=20+19)
HashimotoFullSmall-8      4.90µs ± 1%  4.88µs ± 1%   -0.31%  (p=0.013 n=19+18)