Views2 add mailings

This patch ads the following

Support for civicrm_maling tables (the main tables and the various tracking tables)
I don't know if it's possible but I would like to find a way to have only a true/false for the tracking tables in lieu of one record per event.`
Ads the ability to use the start_date, end_date and scheduled_date field in a calendar
Adds a filter handler for the mailing name field.

All of the above was for a client for whom we went another direction

Add support for hook_date_api_tables dropping the need to add date_api declarations straight into the $data array of hook_views_data.

lastly fixes a bug in handler_filter_datetime