Add support of GIF files in rewrite_images filter, both from HTML and CSS

[GoogleCodeExporter]

As of 0.9.16.6 we don't rewrite GIFs.

IIRC, this is fixed in trunk, adding feature request, so that we keep track of 
this for release-notes.

Original issue reported on code.google.com by sligocki@google.com on 14 Mar 2011 at 6:39

[GoogleCodeExporter]

Original comment by jmaes...@google.com on 14 Mar 2011 at 7:14

• Changed state: Fixed

[GoogleCodeExporter]

Original comment by jmara...@google.com on 6 May 2011 at 4:46

• Changed title: Add support of GIF files in rewrite_images filter, both from HTML and CSS