Merge pull request #483 from nomis52/master

Add build-deps to the debian control file
Introduce the RpcServer class.

This encapsulates the details of handling RPC requests like dealing with
network I/O, client disconnects etc.

This also adds an RpcSession class which can be used to store a pointer to
arbitary user data associated with an RPC client.
Make RpcSessionHandler public.
Merge branch 'master' of github.com:OpenLightingProject/ola