Pierrick Martin / ctools

Update 'test/data/spectrum.fits' to use the new column names

# Conflicts:
#	ChangeLog
#	NEWS
#	README.md

Add tests to csbkgmodel for multi-instrument observations (#2862)

This allows setting the exclusion map without having to save the map first

This enables accessing the generated skymaps without calling 'save()' first

…parameter, and add csbkgmodel unit test