Fabio Iocco / ctools

# Conflicts:
#	src/cttsmap/cttsmap.cpp

So far any exception occuring during the construction of the ctools were not catched. This is corrected now.

All likelihood ctools now derive from the ctlikelihood base class. This avoids code duplication and provides all likelihood tools with a uniform interface.

…cttsmap and cstsmapmerge to the new logging conventions

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

…erLM logger constructor interface (now takes a pointer instead of a reference).

…(see #1360 for details).