Karim Sabri / ctools

…ract ctool::run() method (#3592)

in case `edisp=True`, only use it in practice once the flux calculation is near convergence

- add `_set_src_prefactor` function, which sets the test prefactor while checking that the limits are not violated
- add safety check as part of `_predict_flux`, to avoid division by zero
- add `_sim_evt_excess` function, which is used to increase the test source flux in case the optional conditions on the number of source counts are not met

A _set_source() method was introduced in cssens that deals with the setting of the test source direction independent of the code in the _set_obs() method, since that latter method is not necessarily called. The _set_obs() method now only deals with setting of the pointing direction of a single observation, in case that no observation definition XML file was specified on input.

…ct, csobs2caldb, csobsinfo, csobsselect, and csphagen. The script cstsmapsplit has cslikelihood as base class.

…cripts now from csobservation instead of cslikelihood since they do not use proper optimizers.

The scripts cslightcrv, csphasecrv, cspull, cssens, csspec, cstsdist, and cstsmapsplit now have a "statistics" parameter to allow setting of the optimizer statistic. Except of cstsmapsplit, all of the scripts now derive from the cslikelihood base class.

The new GApplication logger support function take the chattiness level as the first argument.