Fix import in gp-sherpa-like
Add docs/image/survey_example.py
Update image plotting example description
Add GalacticPlaneSurveyPanelPlot and fits_to_png
Install aplpy for travis-ci sphinx build
Fix minor issues with panel plotting
Improve panel plotting
Uncomment aplpy example because aplpy is broken
Merge pull request #100 from cdeil/gps_plotting

Add image plotting routines
Move docs/datasets/formats to docs/dataformats
Add cross-links between dataformats and datasets docs
Update data formats docs pages
Add file formats page to data formats docs.