This commit converts the RPC server over to use the new features available
in the latest version of btcjson and improve a few things along the way.
This following summarizes the changes:
- All btcjson imports have been updated to the latest package version
- The help has been significantly improved
- Invoking help with no command specified now provides an alphabetized
list of all supported commands along with one-line usage
- The help for each command is automatically generated and provides much
more explicit information such as the type of each parameter, whether
or not it's optional or required, etc
- The websocket-specific commands are now provided when accessing the
help when connected via websockets
- Help has been added for all websocket-specific commands and is only
accessible when connected via websockets
- The error returns and handling of both the standard and websocket
handlers has been made consistent
- All RPC errors have been converted to the new RPCError type
- Various variables have been renamed for consistency
- Several RPC errors have been improved
- The commands that are marked as unimplemented have been moved into the
separate map where they belong
- Several comments have been improved
- An unnecessary check has been removed from the createrawtransaction
handler
- The command parsing has been restructured a bit to pave the way for
JSON-RPC 2.0 batching support
