Update imagestats sigmaclip_stats
Replace broadcast_arrays
Do not apply mask to Background outputs
change background names from mesh to lores
Add interp_order keyword to Background
Add reference to Stetson PASP paper
Update .travis.yml
find_peaks threshold must be scalar (scikit-image) [skip ci]
Do not subtract background within SegmentProperties
Exclude extern folder from coverage report
Merge pull request #199 from cdeil/coverage-no-extern

Exclude extern folder from coverage report
Zero negative pixels prior to calculating moments
Restructured main doc page
Minor doc changes
Add new overview page
Add new installation page
Add new getting started page
Add new background page
Remove width/height attributes for banner logo
Put user doc link directly in main doc page