Remove the temporal ordering between the current activity and a2
TODO: This could be an instance method so that additional ordering
information could be added by subclasses, if location parameters need to
be syncronized for instance
A critic that is supposed to display information on resource usage depending
on which resources are used at the current time in the time view
For each activity that is created, a constraint map is maintained that holds
eq constraints for the activity start and end times so that their values
reflect those of the mission time.