simplifying Warsow-style physics code even more, as it now can use a common code...

simplifying Warsow-style physics code even more, as it now can use a common code path with Quake-style physics (the only difference there is is when moving forward only).

This could be done after the observation that CPMA-style acceleration never kicks in in Warsow mode.

The sv_aircontrol is now expected to be zero in Warsow-style mode, as it does nothing in that mode anyway! If you do set it, you get Warsow and CPMA air control added!

git-svn-id: svn://svn.icculus.org/nexuiz/trunk@6686 f962a42d-fe04-0410-a3ab-8c8b0445ebaa