Alexander Ziegler / ctools

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.

…gning the old best optimizer result).

… csspec and complemented the copy constructor of cterror (the optimiser was not copied and intialised)