Michael Mayer / gammalib

# Conflicts:
#	ChangeLog
#	NEWS

The GFft class implements a one-dimensional Fast Fourier transformation. The GFftWavetable class is a support class for GFft and holds the trigonometric coefficients for a factorisation.

An initial implementation of the GNdarray class has been added that implements a n-dimensional double precision floating point array.

…d gammalib::rstrip_chars() function

The gammalib::str() floating point conversion functions now make sure that no precision is lost in a string conversion (well, roughly).

Time setting and getting methods for Julian Days, Modified Julian Days, native seconds and native days are now available that allow specifying the time system. Currently, TT, TAI and UTC are supported.

Methods have also been added that return the Greenwich mean and apparent siderial times, and the local mean and apparent siderial times that depend on the geographic longitude.

Finally, a now() method has been added that sets the time to the current time.

…ients argument (#1847)

The eval_gradients() methods duplicate much of the code of the eval() methods. To increase the maintainability of the code, the eval_gradients() methods have been removed, and the computation of partial derivatives is now done by the eval() methods if the optional gradients argument is set to true.

The application name and version were cleared in a call of the GApplication::clear() method, but these properties should be conserved. Now they are, and a call of the GApplication::clear()  will perform the same actions than a call of the name and version constructor.

The GApplication::log_parameters() method now takes a mandatory GChatter argument to enable displaying of parameters only above a given chattiness level. This avoids a log-level check in the client code. For the same purpose, the GApplication methods log_string(), log_value(), log_header1(), log_header2(), and log_header3() have been introduced (#1828).

# Conflicts:
#	ChangeLog

Python wrappers have been always removed when typing "make clean", even if the wrappers have been shipped with the code. This has been corrected and Python wrappers are now only remove if they actually have been built (and hence if they have not been shipped with the code).

The GModelSpectralRegistry::alloc() method now also checks for the existence of model parameters and allocates the appropriate model from the registry that is found in the XML file base on model type and parameter names. This allows now to have the same model type but different parameter names in the registry.

The spectral model classes have been adapted to the new logic, and models have been added to the registry for all parameter combinations that may exist.

The unit tests and documentation have been updated.

The following new names have been introduced for the spatial model components:
* "PointSource" (alias: "SkyDirFunction")
* "RadialDisk" (alias: "DiskFunction")
* "RadialGaussian" (alias: "GaussFunction")
* "RadialShell" (alias: "ShellFunction")
* "EllipticalDisk"
* "EllipticalGaussian" (alias: "EllipticalGauss")
* "DiffuseIsotropic" (alias: "ConstantValue")
* "DiffuseMap" (alias: "SpatialMap")
* "DiffuseMapCube" (alias: "MapCubeFunction")

There have been several bugs in the energy dispersion computation in GCTACubeEdisp that prevented a correct computation of energy dispersion. This should now be fixed.