Extract HTMLFilter base class from ExcludeTagsHTMLParser Extract a base class from ExcludeTagsHTMLParser that collects filtered HTML output as an HTML document is parsed.
Extract HTMLFilter base class from ExcludeTagsHTMLParser
Extract a base class from ExcludeTagsHTMLParser that collects filtered
HTML output as an HTML document is parsed.

The next patch will add a new subclass for adding attributes to HTML
tags.  The base class avoids duplicating code.

Signed-off-by: Stefan Hajnoczi <484520986196e4a799496429ce8a499eb6488adb@gmail.com>

hsoft/DjangoBB,saifrahmed/DjangoBB,hsoft/slimbb,agepoly/DjangoBB,hsoft/DjangoBB,agepoly/DjangoBB,saifrahmed/DjangoBB,slav0nic/DjangoBB,hsoft/slimbb,slav0nic/DjangoBB,hsoft/DjangoBB,slav0nic/DjangoBB,agepoly/DjangoBB,saifrahmed/DjangoBB,hsoft/slimbb