Bug 869869 - Part 1, change nsUDPServerSocket to nsUDPSocket, r=mcmanus.

--HG--
rename : netwerk/base/public/nsIUDPServerSocket.idl => netwerk/base/public/nsIUDPSocket.idl
rename : netwerk/base/src/nsUDPServerSocket.cpp => netwerk/base/src/nsUDPSocket.cpp
rename : netwerk/base/src/nsUDPServerSocket.h => netwerk/base/src/nsUDPSocket.h
Bug 869869 - Part 2, add PUDPSocket IPDL interface, r=jdm.
Bug 869869 - Part 3, add an IPC implementation of NrSocket, r=ekr.
Bug 869869 - Part 4, add IPC mochitest for PeerConnection, r=bent.