Fix the edit_meeting method to clear our reminder on edit
Add method to clean the database of all its tables
Use the drop_table method from fedocallib.model

This allows to run the unit-tests against faitout or a local postgresql
database and still reset the database for each tests
Small layout changes in the fedocallib tests
Only use drop_tables locally, not when using faitout
Remove the delete method from Reminder -- no longer used
Test Meeting.get_at_date with full_day={True,False}