code cleanups and general performance work to be developed in relative peace.
While cleaning up the networking code /is/ important, fixing QF's perfomance
issues is of much higher priority.
- fix various spots in the above that called Host_EndGame but didn't
return
- switched the order of modellist and soundlist in net_svc*, to
conform with the rest of the files
- create a new CL_ParsePacketEntities, that only handles
svc_packetentities (so it's much simpler). it uses net_svc*
