Include a sample command line json-rpc client

[EggPool]

Any json-rpc client or lib is supposed to be used.
But it would be good to include a command line python client, taking command and parameters from the command line, sending to the server, and printing back the result.

Good as a debug tool, and sample calls.
testing/test1.py can be used as a sample base code, "just" need to wraps up the calls.

I'll do it myself in a few days if noone else did.