Attempt to implement sideway view bobbing as well, for better simulation of steps...

Attempt to implement sideway view bobbing as well, for better simulation of steps (a copy of the current view bobbing code with its own cvars, meant to bob to the side of the player).

This is not ready yet! The commit before this is stable. Still trying to figure out how to make the X and Y axes both work as the player's side.

From: MirceaKitsune <sonichedgehog_hyperblast00@yahoo.com>

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@10290 d7cf8633-e32d-0410-b094-e92efae38249
::stable-branch::merge=0895d56c3531cf7c7e63cd0951abdada67e0912b