Justine Devin / gammalib

tosolve with GVOClient hub discovery mechanism

Public GWcs access method to private members provided

…l skymap content through use of gammalib xml tools.

Rename the methods and do some refactoring and clean up of the code.

Conflicts:
	src/vo/GVOClient.cpp
	test/test_GVO.cpp
	test/test_GVO.hpp

The GModel::has_scales() method signals if scale factors exist for that model.

… "xml_has_par" function and made reading of information in observation definition file optional (so that for example energies or ROI can be missing).

…from HealPix version 3.20.