aded json-rpc.net submodule
removed jayrock based sample server as we can now use json-rpc.net which suports both json 1.0 and 2.0 (jayrock only supports json-rpc 1.0 and for contextial objects we have to hack it using hooks - where json-rpc.net natively supports it).
ClassicService:Getwork() now can correctly handle optional data parameter.
The miners will now be able to submit work correctly now using Getwork(data).