remove sidebarsourcelink block from layout so RTD cant override
Allow scalar and array Quantity objects to be converted to Numpy arrays
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
Fix is_hdf5 for Python 3.x
Merge pull request #607 from astrofrog/unit/quantity-to-array

Allow scalar and array Quantity objects to be converted to Numpy arrays
Remove orphaned io/ascii/version.py file (remnant of asciitable)
Merge pull request #612 from taldcroft/remove-ascii-version

Remove orphaned io/ascii/version.py file (remnant of asciitable)
adjust coordinates initializer to allow specifying bounds
Merge pull request #588 from kbarbary/fix-issue-575

Fix issue 575
Possible fix for #594. I'm a little iffy about this because it feels hackish.  But it adds a new auto-generated module called astropy.utils._cython which contains a cython_version variable recording the Cython version that the Cython modules were last built with.  Technically this module doesn't *need* to be a Cython module, but that ensures that it only exists if the Cython modules were built correctly.  It has the added upshot of forcing the Cython C files to be regenerated if your Cython version has changed since the last build.
Fix typo that caused crash when Cython is not installed
Reworked approach to #594. The cython_version variable is no longer in a Cython module; that was a non-starter since it meant a compiled module would have to be shipped with the source distribution in order for it to know what version of Cython the C files were generated with.  Now there's just a generated cython_version.py that gets touched up any time Cython is used to the build with a different version of Cython from the last time.  This file will ship with the source distribution and its presence will prevent Cython from being used for a release version. But for git clones of a release the cython_version.py *won't* be present and Cython will be used.  So this should cover all the relevant use cases.
Remove unused import left over from an earlier version of this patch
Simplified logical statement and added some comments