added README for Xcode asset project

'DisplayObject.drawToBitmapData' now supports sizes bigger than the s…

…tage / back buffer

raised version to 2.5.1

raised version to 2.5

raised version to 2.4

raised version to 2.3

raised version to '2.2', updated change log

updated changelog for v2.1 final

updated CHANGELOG and gradle build file for 2.0.1 release

updated version infos