Alexander Ziegler / gammalib

The GSkyPixel class now handles 1D and 2D sky indices. This made the distinctive 1D and 2D methods in GSkyProjection and the derived classes obsolete. Now, all projection classes take GSkyPixel as argument.

The GSkymap class now uses the universal GSkyPixel class. Methods have been renamed consistently. An integer index is now consistently called "sky map index" and the GSkyPixel object is named a "sky map pixel". Methods operating on indices contain now "inx", method operating on sky map pixels "pix".

The Healpix pixelisation is not a World Coordinate System projection, and to make this clear the name has been changed from GWcsHPX to GHealpix. The code has been adapted to this new naming convention.

The exception problem has been solved by adding a specific @GExceptionHandler@ catch to the Python interface exception handler. We thus can put back the exception tests.

See Bug #626.

Conflicts:
	test/test_GSky.py