#1207680 by dereine: Don't validate on term filters, because this causes views to not to save anymore

#1040744 by mongolito404: on filter_term_node_tid handler only select all fields from term_data table, so rewritten sql doesn't get confused

#768972 by dereine, cyberwolf and nicedawg: Add an option to disable an error message if terms do not exist on taxonomy term filter.

#662174: handlers with an "extra form" or other option data that was not in the main form could lose that data.

#653628 by dagmar and dereine: Ensure child method declarations match parent method declarations to prevent notices.

Major re-organization of handlers. PLEASE NOTE: This drastically affected the Views module API and until modules are updated to match, they will stop working. Efforts have been made to ensure that this won't cause your site to crash, but that's partly up to the individual module as well.