rpc: implement listreceivedbyaddress

[dajohi]

implement listreceivedbyaddress

[teknico]

From conversation in #btcd@conformal:

davec: the meat of what you'll need is in txstore (http://godoc.org/github.com/conformal/btcwallet/txstore)
davec: in particular I think you'd want to call Records
davec: then range them, grouping by address on the "debits"
davec: well looks more like you just want the balance for each, so you'd use that instead of just debits

[jrick]

This will need to range over the credits for each record, not debits.

[teknico]

Here are two pull requests that implement this call:
btcsuite/btcjson#23
#97