Fix bug - was setting an extra Alert Slider timeout, causing two sliders on initial startup.
Removed the extra timeout as we now use NSITimer exclusively.
Fix bug -  With 2.1.5 changethe lastacknowledge value was now being written outside of the VALARM block (due to the fact that some remote calendars require custom fields to not be in the alarm blocks).  So on startup the lastack is now being looked for outside the alarm block, which would be a problem for all EXISTING events that were previously written with the value inside the alarm block.  So the problem was that backwards compatibility check was not put in place.
Fixed it to look for the lastack in both locations, as well as take into account the case where no lastack value is found at all.
2.1.5.1.1 version bump