Code review

[astrofrog]

No description provided.

[coveralls]

Coverage decreased (-9.28%) to 90.72% when pulling 7d72024 on master into d912f28 on no-code.

[cdeil]

@astrofrog – FYI: @kingj90 and I started to add a gammapy.regions package to Gammapy today (see gammapy/gammapy@master...cdeil:regions#diff-a5281c6e0fa67c34613faf33bb32fef1R156 for a first version), because none of the existing packages (this regions package, photutils apertures or pyregion) really does what we need and work on pyregion is blocked by astropy/pyregion#54 .

This is mostly because we need to have something working for our use cases and merged by next week for PyGamma15. Hopefully gammapy.regions, pyregion and this regions package can be merged into one glorious regions package at some point.