core, tests: implement Metropolis EIP 684

consensus, core, tests: implement Metropolis EIP 649

core/types: encode receipt status in PostState field

This fixes a regression where the new Failed field in ReceiptForStorage
rejected previously stored receipts. Fix it by removing the new field
and store status in the PostState field. This also removes massive RLP
hackery around the status field.

rlp: fix decoding long strings into RawValue types

core: add status as a consensus field in receipt

* cmd/evm, core/vm, internal/ethapi: Add 'err' to tracer interface CaptureEnd

* cmd/evm: fix nullpointer when there is no error

node: fix instance dir locking and improve error message

metrics: change MetricsEnabledFlag to be const

tests: enable Byzantium state tests for CI

Signed-off-by: Ti Zhou <tizhou1986@gmail.com>

vendor: update USB HID lib (fix macOS crash)

core/vm: implement REVERT metropolis opcode

* whisper: Fix spelling and grammar in error

* whisper: Fix grammar in comments

README: add missing full stop

missing period at line 119

The lock file was ineffective because opening leveldb storage in
read-only mode doesn't really take the lock. Fix it by including a
dedicated flock library (which is actually split out of goleveldb).

eth: send but not announce block to peers if propagate is true

cmd/puppeth: support blacklisting malicious IPs on ethstats

core/vm, crypto/bn256: fix bn256 use and pairing corner case