Alexander Ziegler / ctools

Before, if the output file existed, ctskymap appended an extension to this file.

The publish parameter has been added to the following tools:
- ctbin
- ctbkgcube
- ctcubemask
- ctexpcube
- ctmodel
- ctskymap
- cttsmap

…(see #1360 for details).

…)-function of individual ctools

…d scave() methods to ctool interface. Add read_ahead() method to handle reading of task parameters at the beginning of the task execution. Remove all m_read_ahead members from the derived classes.

…nt projections are proposed in parameter file.

GammaLib is undergoing a major interface change which requires adaption of the ctools code.