Added support for SVGZ (i.e. GZIPed SVG).

This is based on work by josefpavlik (https://github.com/josefpavlik/svg-android/commit/fc0522b2e1). However I made an improvement by decorating the InputStream with a BufferedInputStream when mark/reset are not supported.

Signed-off-by: Matthias Stevens <matthias.stevens@gmail.com>
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).
Merge pull request #3 from mstevens83/master

Added support for SVGZ (i.e. GZIPed SVG).