server: improve error message when too many brush models

Check if we are going to overflow our MAX_MODELS allocation and print
a more meaningful error if we will.  This also softens the error to a
Host_Error() instead of crashing in Mod_ForName().

Signed-off-by: Kevin Shanahan <kmshanah@disenchant.net>
server: bump MAX_EDICTS static limit

Signed-off-by: Kevin Shanahan <kmshanah@disenchant.net>
server: bump MAX_MODELS static limit

Signed-off-by: Kevin Shanahan <kmshanah@disenchant.net>
model: Increase precision of lightmap extents calculations

This bug is a counterpart to this bug in quakespasm:
   https://sourceforge.net/p/quakespasm/patches/15/

If the precision of the calculation in WorldToTexCoord done by ‘light’
is significantly different than the precision of the same calculation
in the engine, you can get corrupted lightmaps. The problem affects
light when it’s built as something other than vanilla 32-bit
x86. (e.g. x86_64 on a mac).

Signed-off-by: Kevin Shanahan <kmshanah@disenchant.net>
Merge branch 'master' into atari