Bring on Regex

* HTML_CONSTANTS: Added regex matching features.
* New generated index.html
* ECF: Added gobo regex
* HTML_FACTORY: Added regex testing for various generated tags
* HTML_FACTORY_TEST_SET: Removed is_self_ending, which is now implied as
being opposite of has_end_tag.
* TEST_HELLO_HOME_PAGE: Now uses factory instead of hand_coded_html with
"tag" replacement schema.
* TEST_USER_MESSAGE_HANDLER: removal of is_self_ending