The transaction pool drops processed transactions on its own
during pool maintenance.

Add missing err checks on From()

core: re-add parallel nonce checks

core/vm: improve JUMPDEST analysis

eth/downloader: add a basic block download congestion control

Add EC signature validations before call to libsecp256k1

* JUMPDEST analysis is faster because less type conversions are performed.
* The map of JUMPDEST locations is now created lazily at the first JUMP.
* The result of the analysis is kept around for recursive invocations
  through CALL/CALLCODE.

Fixes #1147

crypto/sha3: pull in latest keccak from go crypto (45% speed increase)

Unsupport bruncles

This reduces the amount of queueEvents that are sent internally.

In this incancation, the processor waits until the nonce
has been verified before handling the block.

Updated SA boot node

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