Merge pull request #35 from SeiferTim/dev

Fixing update and draw logic in FlxNestedSprite
Compatibily with HaxeFlixel/flixel#840
FlxSkewedSprite: add SimpleGraphic param to the constructor
FlxSkewedSprite: a bit of cleanup for the rendering logic
Compatibility with HaxeFlixel/flixel#841
Cpp compile fixes
Compatibility with HaxeFlixel/flixel#850
Optimize asset embedding, HaxeFlixel/flixel#523
FlxNapeState: only embed debug button asset in !FLX_NO_DEBUG
Remove html tags from comments

(includes <code>, </code>, <br> and <br />)
FlxSkewedSprite: make skew (default, null)
Move FlxTrail, FlxTrailArea and FlxSlider to flixel-addons
FlxSkewedSprite fixes for native targets
exposing transformation matrix of FlxSkewedSprite
removing _transformMatrix from FlxSkewedSprite
FlxSlider: fix for destroy()