* core, eth: fix database version

* eth: polish error message

Until this commit, when sending an RPC request that called `NewEVM`, a blank `vm.Config`
would be taken so as to set some options, based on the default configuration. If some extra
configuration switches were passed to the blockchain, those would be ignored.

This PR adds a function to get the config from the blockchain, and this is what is now used
for RPC calls.

Some subsequent changes need to be made, see https://github.com/ethereum/go-ethereum/pull/17955#pullrequestreview-182237244
for the details of the discussion.

* core: return error if repair block failed

* make error a bit shorter

* core/blockchain: better printout of receipts in bad block reports

* fix splleing

* rawdb: remove unused parameter for WritePreimages func and modify a
spelling mistake

* rawdb: update the doc for function WritePreimages

* miner: move agent logic to worker

* miner: polish

* core: persist block before reorg

* core/blockchain: export progress

* core: polish up chain export progress report a bit

The current trie memory database/cache that we do pruning on stores
trie nodes as binary rlp encoded blobs, and also stores the node
relationships/references for GC purposes. However, most of the trie
nodes (everything apart from a value node) is in essence just a
collection of references.

This PR switches out the RLP encoded trie blobs with the
collapsed-but-not-serialized trie nodes. This permits most of the
references to be recovered from within the node data structure,
avoiding the need to track them a second time (expensive memory wise).

* core: improve getBadBlocks to return full block rlp

* core, eth, ethapi: changes to getBadBlocks formatting

* ethapi: address review concerns

* core, eth, trie: streaming GC for the trie cache

* trie: track memcache statistics

* 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

* core: flush out trie cache more meaningfully on stop

* core: upgrade legacy tests to chain maker

* 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

Talk about "state" instead of "trie timing", "trie memory" and remove
the overzealous warning when the limit is just reached. Since the time
limit is always reached on slow machines, move the message to info level
so users don't freak out about internal details.

This commit reduces database I/O by not writing every state trie to disk.

* leveldb: Update leveldb to 211f780 (poolfix)

* core, ethdb: reuse database batches