SendCoin

What's previously been called 'transaction' and 'send' has been renamed 'sendcoin'.

This PR brings back support for transactions in the script api, in the consensus api, in the client, and in the client-cli.

Support for printing all of the wallets being tracked by a particular participant has also been added.
why bother creating the string at all? Why not just print it piece-wise? Strings are immutable, so this function is allocating 10 new strings for every wallet.