Justine Devin / gammalib

… methods from GTools.

Removed size() method.

Renamed filename() method to url().
Renamed fullname() method to operator().

…ilename object. This allows now replacing all std::string filenames by GFilename arguments.

- table(std::string)
- has_axis(std::string)
- has_table(std::string)

The following methods have been renamed:
- GCTAResponseTable::tables(), was formerly GCTAResponseTable::size()
- GCTAResponseTable::axis_bins(), was formerly GCTAResponseTable::axis()

The following methods have been added to the public interface:
- GCTAResponseTable::axis(std::string)

It is still convenient to control the event disposal from the observation class, although the actual event disposal is now handled by the event list class.

…t GCTAEventList level.

If an event list is loaded the actual events are not read in, but only loaded upon request. This allows to save memory.

…ntList::append() method.

… simplify the code for reading and writing of XML files.

…parameter in an XML file.

… method so that they return the correctly return the energy intervals covered by valid matrix elements (#1662).

The former code was not limiting the maximum to the elements covered by the matrix, leading eventually to integration warnings.