core: fix #1154, sort out data race accessing the future blocks

eth: 100% block propogation

Validate account length and avoid slicing in logging

Parallelisation issue

core: log optimisations

Invalid forks are now detected

Current setup of parellelisation actually inserts bad blocks. This fix
is tmp until a better one is found

cmd/geth: updated web3

cmd/geth: leaner blockchain commands

core, eth/downloader: expose the bad hashes, check in downloader

This makes block importing restartable.

Interrupting import with Ctrl-C could cause database corruption
because the signal wasn't handled. utils.ImportChain now checks
for a queued interrupt on every batch.

The renaming should make it clearer that these functions create a new
instance for every call. @obscuren suggested this renaming a while ago.

The blockchain commands don't need the full stack. With this change,
p2p, miner, downloader, etc are no longer started for blockchain
operations.

eth: hard disconnect if a peer is flaky

ethdb, common: cache removal

cmd/geth: expand admin.progress() to something meaningful