Added cl_bob_limit cvar which limits the maximum rage of view bobbing in a smooth...

Added cl_bob_limit cvar which limits the maximum rage of view bobbing in a smooth way (rather than limiting the velocity and cl_bob independently, it limits the strength of the bob before the sinewave is applied).  By default this is 7 (inspired by the quake limit of +4 to -7 range).

Added cl_bob_limit_heightcheck cvar (off by default) which uses tracelines to limit the maximum value of cl_bob_limit based on the ceiling and floor height.

Added cl_bob_velocity_limit cvar which replaces the hard-coded 400 in a few places for xyspeed purposes.

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@12286 d7cf8633-e32d-0410-b094-e92efae38249