Matteo Balbo / ctools

…ts the intervals, leading in the worst case to an empty event list if no overlap exists.

…o 1051-create-ctbutterfly

…odel with a standard diffuse cube background model that can be used for stacked analysis. The model container can be either retrieved using the models() method, or it can be written to disk with the save() method.

The tscalc parameter has been removed from ctlike.

…problem or a Python problem).

Conflicts:
	ChangeLog
	NEWS

As the GCTAObservation class now handles transparently the disposal and re-loading of information it is not needed anymore to re-load the event list upon call of the obs() method. We thus can put the obs() method inline as before.