Updated database to version 0.0.13 to get rid of some old fields.

Updated database to version 0.0.13 to get rid of some old fields.
Removed those fields from the related data classes.
Added information on available dates and times to the registration page on the front-end.
Now need to put in pop-up calendar for date selection for time_specific registrations.
Added functions to purge expired reg_time_pending entries and to update the quantities in the reg_time table.
Improved display of reg times in the event dashboard in admin.