Reworked some of the autoplay logic in LLViewerMediaImpl to try and make it more consistent when media is unloaded and reloaded by the performance manager.
LLViewerMediaImpl will now keep track of the media state and current time of media that it unloads for performance reasons, and attempt to restore playing or paused media to the same playhead time and state (playing or paused) when it reloads.
Added "done" status that time-based media plugins can use to indicate that they've reached the end of the media and stopped.
Added logging of priority transitions, for use in debugging issues with the peformance manager.
svn merge -r 129913:131718 svn+ssh://svn.lindenlab.com/svn/linden/branches/pluginapi/pluginapi_05
Some branch shenannigans in the pluginapi_05 branch caused this to become a two-part merge.
Rye