Have separate variables for setup_requires and install_requires.
Merge pull request #1561 from mdboom/setup/install-requires

Add separate variable for install_requires
Merge pull request #732 from astrofrog/table-set-units-from-quantity

Set column units when initializing Column or Table from a Quantity
Control whether metadata merge conflicts result in a warning, an error, or nothing (only in vstack for now)
Improved description for ``metadata_conflicts`` and add the option to ``hstack`` and ``join``.
Ensure that an exception is raised if metadata_conflict is not one of e expected values.
Fixed typo
Use custom warning class
Always pick the right key
Added tests for metadata merging with hstack, vstack, and join
Started working on also providing control over metadata conflict errors/warnings for column metadata
For merging unit, format, and description metadata, always pick the last one
Extend metadata conflict control to column attributes (unit, format, description) and improve consistency.
Added documentation for conflict resolution of metadata
Added entries in CHANGES.rst
Whitespace
Fix typo