WIP: background maps
Fix data padding
Add SE skewness test for background meshes
Improve background masks
Add global background/rms median property
Clean up resize methods
Add background API docs
Add Background filter_threshold
Fill background mesh arrays
Reduce background memory usage
Add custom background method
Prevent zero division in background skewness test
Background improvments
Add background tests
Handle small background grid sizes
Use zoom instead of RectBivariateSpline in Background
Change default background sigclip_iters to 10
Use scipy.stats.nanmedian if numpy < 1.9
Use alterative pad function for numpy <= 1.6
Merge pull request #192 from larrybradley/background

2D background and rms noise estimation