-Looping syncslaves are stopped when there is no syncmaster.
-Hardened against edge cases regarding soundsource priority sorting.
-Fixed issue with syncmasters being marked as having looped when instead they just started playing (caused double-start of syncslaves).
-Updated some comments.
Added stricter checking for fmodex errors.
Demote a harmless message from llinfos to lldebugs when audio buffers are all consumed.
Initialize LLAudioBuffer member variables.
-LLAudioBuffer::mInUse is inited to TRUE to avoid buffers that just got created from getting deleted during the same frame by new audio sources further down the chain.