Issue #46: Documented more python files

Documented electrum/meat/ngccc*/pwallet/rpc_interface.

Fixed ui/qtui since the api changed to be lookup_by_moniker.
Added setval/getval to rpc_interface.
Refactored ngccc* to be simpler python scripts.

Took out a couple of functions nobody used.
Merge pull request #49 from jimmysong/46

Issue #46: Documented more python files