Tests
- Use standard tests.

Config file & command line options.

Peer network.

Trie on DB.
- Modularise overlay and DB.
- Iterate.
- Kill all the restore point stuff.

Cache some state
- Contract memory, balances - for single commit into Trie.

Better handling of corrupt blocks.

Stateful Miner class.

Better Mod-Exp.

Crypto stuff:
- kFromMessage
- Check all the tweak instructions.