added PRVM_64 define which upgrades the QC VM to double precision

added PRVM_64 define which upgrades the QC VM to double precision
variables (such that levels can run for more than 24 hours without
time precision breakdown, and bit arithmetic can be done on 52 bit flags
rather than 23 bit flags)
changed csqc setmodel builtin to do setsize as well (like on server)
fixed multiple bugs where csqc builtins were passing right as left in a
matrix conversion

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@11785 d7cf8633-e32d-0410-b094-e92efae38249