Bundle imageutils and update photutils to use latest API
Merge pull request #132 from astrofrog/bundle-imageutils

Bundle imageutils for photutils 0.1 release
Tidy up aperture_funcs.py to avoid duplicated code
Simplify center mode since using subpixel mode with subpixels=1 is actually faster (by at least 50% in some cases)
Remove imageutils from .travis.yml
Merge pull request #162 from astrofrog/tidy-up-funcs

Tidy up aperture_funcs.py to avoid duplicated code
adding do_rectangular_photometry function
adding do_rectangular_photometry usage to aperture_core
minor docs change
adding rectangular annulus aperture
remove check for zero lenght aperture side
Adding test
removing repeated lines
Fixing code and tests to pass tests