* rpc: return unordered transactions in pending transactions filter
* ethcore: use LruCache for nonce cache
Only clear the nonce cache when a block is retracted
* Revert "ethcore: use LruCache for nonce cache"
This reverts commit b382c19abdb9985be1724c3b8cde83906da07d68.
* Use only cached nonces when computing pending hashes.
* Give filters their own locks, so that they don't block one another.
* Fix pending transaction count if not sealing.
* Clear cache only when block is enacted.
* Fix RPC tests.
* Address review comments.