make driver (library) name configurable
move presentation code to vdpau-presentation.c file
move presentation queue display to another thread
expose global locking in vdpau-locking.h
basic VdpPresentationQueueBlockUntilSurfaceIdle implementation
return correct first_presentation_time from VdpPresentationQueueBlockUntilSurfaceIdle
use clock_gettime in VdpPresentationQueueGetTime
track surface status and return it from VdpPresentationQueueQuerySurfaceStatus
update implementation status of presentation queue functions