Eirik Hatlen / gammalib

…ng now use of the new PA.

…lemented a cludge for computing the overlap of rectangle-rectangle.

…ethod contains_local(GSkyDir). Implemented contains(GSkyRegion) for rectangle.

… (ds9 line) and written to ds9 string. Can be set via radians and degrees, the latter is implemented for the constructor. Changed solid angle computation algorithm.

# Conflicts:
#	ChangeLog
#	NEWS
#	README.md
#	configure.ac
#	doc/Doxyfile
#	doc/source/admin/release_history/index.rst
#	doc/source/conf.py
#	sonar-project.properties

The GCTAModelIrfBackground::eval() method uses now the GCTABackground3D::rate_ebin() integrator method instead of the GCTABackground3D::operator() operator so that the background model evaluation is no longer sensitive to the number of energy bins.

The GCTACubeBackground::fill() method was simplified, removing the power law integration which was not accurate enough, and using directly the GCTAModelIrfBackground::eval() method which is now exact.

…and writing to the XML file of the associations (#3469)

This assures that spatial parameters that are fixed during the model fitting are correctly taken into account.