Copy a symbol's transform's properties over to DisplayObject's during initialization

Instead of just assigning the transform to DisplayObject#_currentTransform. Otherwise, instances of a DisplayObject class, share their transforms, so changes to the position of one of them will be reflected in all of them. Which is kinda bad.
Correctness fixes to how TextFields are positioned and rendered. Lots of them.
Reftest for TextField alignment and auto-sizing
Merge pull request #730 from tschneidereit/master

TextField fixes, lots