Remove lxml requirement from error parsing

LXML is overkill and not really required to make a decent error string. This is my take at a reasonable alternative to the htmlsoup parsing, removing a couple dependencies. While the htmlsoup parsing could be considered flexible it is still much more dependent on present form html structure than need be. I think the H1 will be long term more reliable error string than the more complicated pathing required of the current algorithm. Either way we are betting on the future output of an external project (solr + tomcat), and writing pretty fragile code. 
I think it'd be cleaner to simply write this as a regex which would also handle cases like something breaking in a way which doesn't send </h1>, adding classes or other attributes to <h1>, etc.