Remove mask interpolation from segmentation; now separate function
Move utility functions to utils
Remove mask_method from aperture_photometry
Fix method description
Apply mask to error array in aperture_photometry
Improvements to mask interpolation
Add tests for prepare_data
Merge pull request #179 from larrybradley/mask_api

Implement new masking API
Add filter_kernel option for detection
New test for filter_kernel
Add new tests for detect_threshold
More tests for detection
Cleanup of detection module
Move morphology from detection
Add mask option to gaussian1d_moments
Add error and mask option for centroid_1dg
Modify morphology functions to SegmentProperties
Clean up morphology functions
Add morphology tests
Add segmentation.rst