whisper: refactor wnode to systematically store messages if a directory is provided

* core: make current*Block atomic, and accessor functions mutex-free

* core: fix review concerns

* core: fix error in atomic assignment

* core/light: implement atomic getter/setter for headerchain

* Fixed broken link to JavaScript-Console wiki in cmd line help

* cmd/geth: Added missing r in 'JavaScript'

swarm: creates Swarm landing page for browser 'localhost:xxxx/' GET request when running Swarm (#15926)

* swarm: began work on GetHandleFile method re: issue #155

* swarm: now able to serve landing page template

* swarm: added landing page template

* swarm: landing page has working input

* swarm: fixed CSS issue in template

* swarm: deleted extra lines

* swarm: deleted time header and made redirect a relative path

* swarm: removed code mistakenly left

whisper: filters no longer get removed after a while

* swarm: initial instrumentation with go-metrics

* swarm: initialise metrics collection and add ResettingTimer to HTTP requests

* swarm: update metrics flags names. remove redundant Timer.

* swarm: rename method for periodically updating gauges

* swarm: finalise metrics after feedback

* swarm/network: always init kad metrics containers

* swarm/network: off-by-one index in metrics containers

* swarm, metrics: resolved conflicts

Without this, deprecated bzzr requests just return an empty response.
Signed-off-by: NLewis Marshall <lewis@lmars.net>

whisper: light client mode introduced

* core: flush out trie cache more meaningfully on stop

* core: upgrade legacy tests to chain maker

Fix race condition in whisperv6/peer.go

* core, vm, common: define constantinople fork, start implementation of shift instructions

* vm: more testcases

* vm: add tests for intpool erroneous intpool handling

* core, vm, common: fix constantinople review concerns

* vm: add string<->op definitions for new opcodes

* go-metrics: fork library and introduce ResettingTimer and InfluxDB reporter.

* vendor: change nonsense/go-metrics to ethersphere/go-metrics

* go-metrics: add tests. move ResettingTimer logic from reporter to type.

* all, metrics: pull in metrics package in go-ethereum

* metrics/test: make sure metrics are enabled for tests

* metrics: apply gosimple rules

* metrics/exp, internal/debug: init expvar endpoint when starting pprof server

* internal/debug: tiny comment formatting fix

eth, les, light: filter on logs only, derive receipts on demand

swarm: repeated --ens-api CLI flag (#14386)

* p2p: remove unused code

* p2p: remove unused imports

RPC Server readRequest method sets the serverRequest error service
value as the rpcRequest.method and this change sets it to the right
service value.

core: yeah, funny file, drop it

p2p/protocols, p2p/testing: protocol abstraction and testing

cmd/faucet: resolve twitter user from final redirect

cmd/puppeth: Don't allow hyphen in network name. Fixes #16155

accounts/abi: Fix the bug of mobile framework crashing

accounts/abi: add another unpack interface