Wallet Update

The wallet now updates when you ask for the balance. The update should be thread-safe and accurate, and should include unconfirmed transactions (excluding those with storage proofs, but our software will never put money sends in the same transaction as a storage proof).

Also not tested.

My future plans are to bring back the api, and then add a bunch of testing around the wallet and tpool and consensus code to make sure things are running smoothly.

Then we can test things live and see if we can check off points one and two in issue #296 (closed). My guess is that the synchronization code needs work.