* common: all golint warnings removed

* common: fixups

travis, appveyor: update to Go 1.10.3

Prior to this change, when geth was started with `geth -dev -rpc`,
it would report a network id of `1` in response to the `net_version` RPC
request. But the actual network id it used to verify transactions
was `1337`.

This change causes geth instead respond with `1337` to the `net_version`
RPC when geth is started with `geth -dev -rpc`.

* vm/test: add tests+benchmarks for mstore

* core/vm: less alloc and copying for mstore

* core/vm: less allocs in sload

* vm: check for errors more correctly

This commit adds all changes needed for the merge of swarm-network-rewrite.
The changes:

- build: increase linter timeout
- contracts/ens: export ensNode
- log: add Output method and enable fractional seconds in format
- metrics: relax test timeout
- p2p: reduced some log levels, updates to simulation packages
- rpc: increased maxClientSubscriptionBuffer to 20000

 #15685 made peer_test.go more portable by using random free port instead of hardcoded port 30303 (#15687)

Improves test portability by resolving 127.0.0.1:0
to get a random free port instead of the hard coded one. Now
the test works if you have a running node on the same
interface already.

Fixes #15685

console/console: correct some comments typo

core/asm/lexer: correct comments typo

This PR fixes a retriever logic bug. When a peer had a soft timeout
and then a response arrived, it always assumed it was the same peer
even though it could have been a later requested one that did not time
out at all yet. In this case the logic went to an illegal state and
deadlocked, causing a goroutine leak.

Fixes #16243 and replaces #16359.
Thanks to @riceke for finding the bug in the logic.

ToECDSAPub was unsafe because it returned a non-nil key with nil X, Y in
case of invalid input. This change replaces ToECDSAPub with
UnmarshalPubkey across the codebase.

internal/ethapi: reduce pendingTransactions to O(txs+accs) from O(txs*accs)

metrics: fix gofmt linter warnings

* ethdb: gratefullly handle quit channel

* ethdb: minor polish

* core/rawdb: use wrappered helper to assemble key

* core/rawdb: wrappered helper to assemble key

* core/rawdb: rewrite the wrapper, pass common.Hash

trie: don't report the root flushlist as an alloc

rpc: support returning nil pointer big.Ints (null)

* core: improve getBadBlocks to return full block rlp

* core, eth, ethapi: changes to getBadBlocks formatting

* ethapi: address review concerns

The error produced when using a Parity RPC was the following:

ERROR: transaction did not get mined: failed to get tx for txid 0xbdeb094b3278019383c8da148ff1cb5b5dbd61bf8731bc2310ac1b8ed0235226: json: cannot unmarshal non-string into Go struct field txExtraInfo.blockHash of type common.Hash

This change introduces 

    ethkey changepassphrase <keyfile>

to change the passphrase of a key file.

optimization code