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)
Just as in JavaScript, strict equals should always be used unless you have a reason not to. 

Switch-case lends itself well here since you could imagine additional values being added that would require extending this if/elseif/else structure.

It's fine to keep using if statements, but you should really use strict equals at the very least.