Batch of fixes for the cl_cin code in MP (from ioq3)
- "From ludwig: Unsigned overflows don't work in 64bit address space ..."
- "Removed seemingly unnecessary OS X implementation of yuv_to_rgb24"
- "use memcpy for copying stuff around to fix alignment problems"
- "Removed strange MacOS X #ifdeffery from cl_cin.c (from tjw)"
- "fix crash with videos on ppc (bugzilla#2523,3802). Patch by Przemysław Iskra"
- "Allow ingame videos to be re-enabled (bugzilla#4744)"
- "Support non-256x256 videos in shaders, by Zack Middleton (bugzilla#4745)"
- "Fixed some function name comments in cl_cin.c"
- some gcc 4.3 warning fixes
- Removed streaming file usage from cl_cin (its unused anyway)