not including cancelled timeslots in counting treatments for rezepte

Has a serious performance hit when joining the whole timeslot table into
the query... to be expected. Need to investigate if I can improve that
somehow. Indexing by certain columns? Check the FK constraints?
tieing in cancelled attr into link_timeslot_rezept
adding buildSearchDict func to link_timeslot_rezept
refactored setAusfall!! working nicely it seems
changed REPLACE INTO to UPDATE for all (?) classes
enforced init() to use buildSearch*Dict func
more fixes, upgrading timeslotForm for changes