Prefetch and html washing additions.

Prefetch and html washing additions.

2010-09-19  Julien Danjou  <julien@danjou.info>

	* gnus-html.el (gnus-html-prefetch-images): Use `url-retrieve' rather
	than curl.
	(gnus-html-image-fetched): Fix `gnus-html-put-image' call not setting
	the right URL and ALT text on images.
	(gnus-html-wash-tags): Fix tag case.
	Add support for `s' and `ins' tags. Use gnus-emphasis-* faces.
	(gnus-article-html): Add -o display_ins_del=2 option.
	(gnus-html-wash-tags): Add better support for <ul> tags symbols.