Make inline SVGs work in shr again

* net/shr.el (shr-dom-print): Don't print comments.
(shr-tag-svg): Give inline SVG images the right type.
biditest: Change maintainer to emacs-devel rather than FSF.

The same thing was done for other files a while ago.
Correct ChangeLog attribution

Ref thread: http://lists.gnu.org/archive/html/emacs-devel/2014-12/msg00306.html