Add imageutils and reproject as dependencies for Gammapy
Merge pull request #161 from cdeil/reproject_imageutils_dependencies

Add imageutils and reproject as dependencies for Gammapy
Updates load script for changes in FermiVelaRegion and adds load script fermi PSF for this region
Updates test script to accound for changes and additions in load script for FermiVelaRegion class
Updates load script to include cutout of fermi diffuse background model gll_iem_v05_rev1.fit for the vela region
Updates test script to test load of Fermi diffuse model
Merge pull request #162 from ellisowen/vela_region_changes

Vela region changes
Implemented distributions as astropy models

Conflicts:
	gammapy/astro/population/spatial.py
Changed all models to astropy models added testing and docs
Changed code to use quantities