fixes #172
added a check in SweetDreamsMain to see if the timer is <= to 0. if so close application. This resulted in the application
closing if the exit on finish was selected because the timer is always 0 or less than if it isn't running.
modified line in Service for when timer is decreased to stop at 0.

in short. the issue was being that the timer only had two states. it was either -1 or above zero. if the timer was -1 it represented both the timer was complete
and that a timer never existed. thus the application would not close. modified the timer to be at 0 if the timer never existed and -1 if finished. above zero
represents still in play