Change interpretation of lists in Table.__getitem__ (closes #274)
Duck type when item in __getitem__ is not one of a few specified possibilities
Add tests and documentation for getting sub-set of columns with list of names
Clarifying updates about affiliated packages
Re-introduce basic sanity check on slice in Table.__getitem__
Add a system whereby collections of units can be enabled after the fact.
Remove imperial units from examples
Fix documentation typo
Add astropy.units.imperial.enable
Add examples to add_enabled_units_context
Merge pull request #1454 from mhvk/table-getitem-with-list

Allow lists to select multiple columns in Table.__getitem__ (closes #274)
Merge pull request #1268 from mdboom/unit/enabling

Allow sets of units to be enabled
Initial GroupedTable functionality: create table with indexes
Add basic aggregate method
Allow for numpy array input for groupby keys
Simplify _groupby by using Table methods
Add column aggregate method
Make aggregate return columns of same class as original
Allow for group_by keys to be Table
Update table meta for output of aggregating