Add listscripts RPC command handling
Add listscripts RPC command handling

The listscripts RPC command has been added, allowing a user to dump
the redeem scripts contained by their wallet. The dumped redeem scripts
also include the 20-byte HASH160 script hash and the script hash
address.

decred/dcrwallet,jrick/dcrwallet,jrick/dcrwallet,decred/dcrwallet,jrick/btcwallet,jrick/btcwallet