rewrote r_speeds stats code, now uses renderstats global structure rather than indivi...

rewrote r_speeds stats code, now uses renderstats global structure rather than individual c_ global variables, this makes maintenance a lot easier, additionally changed all the stats to be more representitive of how the engine actually works (counting entities instead of models/bmodels/sprites separately, among other changes), condensed r_speeds stats display to fewer lines

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@5756 d7cf8633-e32d-0410-b094-e92efae38249