[MP] Merged critical fixes (ioquake/ioq3@f725b23) for snapshot floating point imprecision from ioq3 that were missing.

Also merged: part of ioquake/ioq3@e41d081
* Loopback clients only get snapshots at the server frame rate now
  (Anonymous <nkylqinhvgcbyl@mailinator.com>)
* cl_lanForcePackets. When set to 0 (default is 1) the cl_maxpackets setting
  will be ignored if on a LAN. (Anonymous <nkylqinhvgcbyl@mailinator.com>)