Add a wallet type app

[kladskull]

Currently you have to send data to the network via code, we need to create a simple wallet app (command line first) that will assemble a transaction and send it.

• should use the most optimal unspents (if there is a 4 coin unspent tx, and a 50 coin unspent tx, and we send 2 coin, it should use the 4 coin instead of one big one)
• Add ability to create new wallet
• need to encrypt the private keys with a password
• main program shouldn't require the encrypted wallet private key (only the wallet app)

[kladskull]

likely need to communicate with the client using the local port. Don't want to use pipes