Added SVGDrawble. Unlike the PictureDrawable returned by SVG.getDrawable() this PictureDrawable subclass correctly renders in ImageView with FIT_XY scaling (http://developer.android.com/reference/android/widget/ImageView.ScaleType.html)

This class was originally written by nimingtao (ADET project): https://code.google.com/p/adet/source/browse/trunk/adet/src/cn/mobileww/adet/graphics/SvgDrawable.java?spec=svn25&r=25
He reported a drawing problem in ICS devices but I have not been able to reproduce it (i.e. it works fine).