setting number of quads to zero in QuadBatch dispose method

That should prevent any problems when the batch is rendered after it was disposed. While that's not a good practice, it's better if the framework doesn't fail in that situation.
added missing text texture disposal (closes #415)
updated ATF file parsing for latest format
AssetManager name extraction now ignores URL parameters (closes #420)
fixed extension parsing when working with URL parameters (refs #420)
avoiding compiler warning in Flash CC (closes #422)
small 'Quad.set color' optimization (refs #424)
avoiding multiple dispatching of 'addedTo'- and 'removedFromStage' events (closes #426)
new parameter 'transparent' on 'stage.drawToBitmapData' (closes #427)
raised AIR version to 3.9
removed internal closure in 'draw' method to avoid GC issues (closes #417)

Thanks to Jonathan Hart for the fix!
added some information about profile limitations of 'Stage.drawToBitmapData' (refs #427)
Merge branch 'master' into develop