JSURLStream.as : move two methods from private to protected to allow their extension
fix https://github.com/mangui/HLSprovider/issues/100
add debug traces to track audio/video timestamp differences
accurate seeking : fix keyframe detection
only consider video keyframe.
avoid video keyframe to be dropped by "accurate seeking algorithm" in case video start just before audio
fix https://github.com/mangui/HLSprovider/issues/99
Merge branch 'master' of https://github.com/mangui/HLSprovider

Conflicts:
	src/org/mangui/HLS/streaming/FragmentLoader.as
change the way of reassembling PES data.

Don't reset accumulated data at each TS fragment.
Accumulate PES data for audio and video until we have a payload start indicator,
then assume the pes is complete and continue with the next pes.
When changing audio track discard current data.