This makes it possible to send wsh commands from wsh on a remote session
to wavesrv running locally. The exact behavior of running those commands
isn't implemented, but the underlying interface is added here.
lots of changes. new wshrpc implementation. unify websocket, web,
blockcontroller, domain sockets, and terminal inputs to all use the new
rpc system.
lots of moving files around to deal with circular dependencies
use new wshrpc as a client in wsh cmd
