quake: merge some fixed-point optimizations from PocketQuake

The PocketQuake project, available below, has some nice fixed-point code:

https://web.archive.org/web/20150412233306/http://quake.pocketmatrix.com/PocketQuake0062_src.zip

I'd like to see most of them merged into our Quake port. This commit
gives +0.9FPS on ipod6g. (A big change given that it was running at
only 9.7FPS to begin with!)

Change-Id: I91931bdd5c22f14fb28616de938a03b4e7d7b076
10 files changed