Use the safe tempfile.NamedTemporaryFile in SExtractor unit test.
Add unit test for np_to_pha function.
Move image_to_hdu to pyfact.py
Temporarily add PyFACT stuff in gammpy/utils/pyfact.py
Add some entries to docs/references.rst
chmod scripts to be executable
Move over `sim_evlist` and `create_spectrum` from PyFACT
Add `EnergyDispersion.apply` method
Add `gp-pfmap` script (adapted from `pfmap` script from PyFACT)
Add `gp-pfsim` script (adapted from `pfsim` script from PyFACT)
Whitespace formatting cleanup
Add gammapy/utils/scripts.py and use it in all command line scripts
Add `gp-pfspec` command line script (was `pfspec` in PyFACT)
Add scripts/gp-xspec file