Pierrick Martin / ctools

A FFT-based computation was implemented in ctskymap for the RING background, which is faster but less accurate than the direct computation.

… Also implement OpenMP support for multiple observations.

Removed 'runavgalpha' option, since computing the run-by-run significance is a non trivial thing and the difference in the residual counts map is negligible.
Added special handling in the significance computation when Non=0 to avoid NaN's.

…tskymap_RING_bkgsubtract

Updated help text in ctskymap.rst
Added parameter in ctskymap to allow computing ring alphas run-by-run or as an average over all runs
Implemented run averaged computation of ring alpha parameters.
Added caching of pixel directions to prevent numerous calls to 'GSkyMap::inx2dir()'.
Removed 'm_cnts' variable, using m_skymap instead to store individual run counts when doing "RING" subtraction.

Implemented the ring background subtraction method to ctskymap.
Tests are still to come.

Fixed the method names for G_BIN_EVENTS and G_BKG_SUBTRACT_IRF, which were incorrectly set to older method name values.
Added G_BKG_SUBTRACT_RING definition for the ring background subtraction method.
Added definition of parameters in 'ctskymap::get_parameters()'.
Added method for computing the ring background subtraction (skeleton).
Added parameters for defining the ring and integration source region integration radius.
Added configuration parameters to parameter file.
- roiradius: Region of interest radius
- inradius: Inner ring radius
- outradius: Outer ring radius
- regfile: Region file (or FITS mask file) for exclusion regions.

…l integration in ctskymap (#1975)

The ctobservation::first_unbinned_observation() and ctobservation::next_unbinned_observation() methods implement an unbinned CTA observation iterator. Using this iterator avoids code duplication and generates a uniform interface for tools to loop over CTA events lists.

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

…)-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.

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