Preperation for checking lunchtime clashes.
Fixed serious bug in SimpleTimeslot.
Timeslots starting at the same time did not clash. Added extra test to
keep track of this.
Duration not important in timeslot comparison, only start SimpleTime
Addition of minutes to function to help with lunch break clash detection
Improved lunchtime constraint test
Cleaned up Schedule class
by adding and reusing a method for sorting activities
Fixed typo in penalty setter
Didn't I just stage lunch break clash source improvements???