added test_imports to make sure all packages successfully import
added open_api_page function
Initial version of the astropy.constants docs
Merge pull request #528 from eteq/quantity-add-numerical-converters

Add numerical converters to Quantity
Merge pull request #599 from mdboom/unit/steradian_radian

Make steradian and radian ** 2 units equivalent?
Merge pull request #449 from mdboom/unit/add_equiv_kwarg

Add support for `equivs` kwarg on `convert_units_to`.
Merge pull request #602 from mdboom/unit/fits-parser-whitespace-handling

Improve whitespace handling in astropy.unit.Unit FITS format string parsing?
FITS unit format doesn't support floating-point powers, only fractional powers, so care must be taken when the power is represented by a floating-point number.
Fix for Python 2.6 for missing functionality in the fractions stdlib module.

Conflicts:
	astropy/units/core.py
Add equivalency for f_nu <-> nu * f_nu
Add equivalency for f_lambda <-> lambda * f_lambda
Add an option to use names over IDs when converting a VOTable to a Table.
Add use_names_over_ids support to votable's connect.py
Merge pull request #589 from iguananaut/issue-589

pip install of astropy broken
Update docs/development/workflow/maintainer_workflow.rst

Added guidelines on using milestones and backport labels in the github ticket system.  Will add more later on the actual backport process.
Update docs/development/workflow/maintainer_workflow.rst

Fix rst formatting
Update docs/development/workflow/maintainer_workflow.rst

More rst formatting fixes; this will teach me not to preview
include all cosmology functions as methods of the cosmology object
remove now-incorrect sentence from cosmology docs
Fixes #622.  Add methods to look up elements by utype.