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 
(dimensions of stage and levels could be Numbers so it's not a good practice to make them int)
@aneebq in this case there is no difference between strict equals and not strict - we are comparing strings. Usage of switch-case is disputable. I'm not a big fan of this structure. Anyway in this situation the switch-case breaks could be easily confused with breaks inside for loop. Functionally there is no difference. It's also much more solid construction IMHO than switch-case block.