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.
- rename the message argument of NET_SVC_*_Parse to msg
- rename the other argument to block, for brevity
- convert svc_spawnstaticsound
- convert svc_serverinfo
- convert svc_playerinfo
- fix a exploitable buffer overflow with svc_lightstyle