Fixing issue with hls_live_flushurlcache

This was broken with the introduction of data URIs

Issue: https://github.com/mangui/HLSprovider/issues/238
Merge pull request #239 from aneebq/fix-for-hls-live_flushurlcache

Fixing issue with hls_live_flushurlcache
Fix and improve caping max level to player stage dimensions
- now the stage dimensions are properly detected through stageWidth & stageHeight properties
- capping is now based on two dimensions width and height
- if the stage size was changed during the playback the autoswitching will now consider new max_level value to switch up or switch down the stream level (no matter if the bandwidth was changed)
- the autoswitching mechanisms are runed only if the stream has more than 1 level
- HLSMaxLevelCappingMode enum class defines two possible max leve capping modes:
	- HLSMaxLevelCappingMode.DOWNSCALE - max capped level should be the one with the dimensions equal or greater than the stage dimensions (so the video will be downscaled)
	- HLSMaxLevelCappingMode.UPSCALE - max capped level should be the one with the dimensions equal or lower than the stage dimensions (so the video will be upscaled)

related to #165

Conflicts:
	src/org/mangui/HLS/streaming/AutoLevelManager.as
Update README and test files related to cap level to stage options