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 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
Fixes #622.  Add methods to look up elements by utype.
This file was merged into the wrong path in cb09f8f0; I already restored the file to its right location in 8a892b51 but it still hung around here.
Merge pull request #498 from eteq/generate-config-at-install

Changes config package to generate a default config file at install and puts it in the users's astropy directory at first import of astropy
added changelog entry for #498
Update the *_by_utype methods to support returning multiple values
Merge pull request #615 from mdboom/data/multiprocessing

multiprocessing fixes for downloads
Fix for Python 2.6
Merge pull request #639 from mdboom/setup/pkg_config_warning

Warn when pkg-config fails