Uncomment checksum assert in IRF tests
Begins implementation of image from source catalog script
Adds to gammapy.datasets scripts to load fermi extended source catalog images
Adds fermi extended sources test case
Merge pull request #152 from ellisowen/extended_sources

Extended sources
Adds FermiVelaRegion load scripts to datasets
Adds unit test for Fermi Vela Region
Adds supporting changes in setup_package.py for new FermiVelaRegion class
Merge pull request #156 from ellisowen/fermi_source_data

Fermi source data
Adds initial code
Merge branch 'master' of https://github.com/gammapy/gammapy into image_from_catalog