Moved SFXStatus enum to SFXBase.
Removed debug output.
Avoid calling querying the openal status in getStatus (which causes
a slowdown of sfx).
Add volume, speed, and position settings to be done by the sfx
thread. Removed more unnecessary error checks (which mostly flood
stdout with 'not playing ...' messages), and renamed volume, position
and speed to setVolume, setPosition and setSpeed.
Merge branch 'master' of github.com:supertuxkart/stk-code