GammaLib

So far the GEbounds methods do nothing if an energy interval is empty (emin = emax) or invalid (emin > emax). This can lead to a situation where the user thinks that he has appended an interval, but the interval does not exist.

There is no reason for not having empty energy intervals (emin = emax), hence such intervals should be allowed.

In contrast, appending invalid energy intervals should raise an exception.