Add a system whereby collections of units can be enabled after the fact.
Add additional units in CDS/Vizier format
Move % and --- to the cds.py unit collection
Make Crab completely CDS-specific
Fixups after rebase
Fix doc build by using an approach that will get unicode attributes on modules correctly on Python 2.x
Add a list of distutils commands that don't require downloading dependencies.
Allow for `kind` kwarg to Table.argsort
Use mergesort alg for groups sorting to maintain order
Fix for #1579
Added import statements to run examples individually
Fixed 2D and 3D convolution 'None' mode
Changed default of convolve to 'fill'
Canged import order and removed blank lines
Removed redundant complex type check
Added masked array and normalize function tests
Added boundary=None for list test
Fixed masked array handling in convolve_fft
Changed docs to new default behaviour
Enable coverage testing and publishing to coveralls.io