WebComment: better support for ordered and nested lists

• Extends/changes functions 'handle_starttag(..)', 'handle_endtag(..)', 'handle_data(..)' in order to improve the support when sending the email notification:
  • Improves the transformation for ordered, unordered and nested lists.
  • Detects links like: '<a href="http://foo.com">http://foo.com</a>' and tranforms into 'http://foo.com'. (closes #764)