Merge pull request #1989 from eteq/angleemptysepstring

Allow `sep` on `Angle.to_string` to be empty
Merge pull request #1991 from taldcroft/ascii-names

Fix problem with names arg colliding with existing names
Fix conesearch test failure under Python 3.4
Merge pull request #1972 from mdboom/vo/order-independent-comparison

Do dictionary-order-independent comparison in test_printcat
whitespace
Ignore warning only on Python 3.4
update overview.rst to better reflect current affiliated package scheme
Move change log entry to correct section
Started replacing several interfaces with cross-compatible versions from six.  Still most tests failing.
Gets the remaining of the io.fits tests passing nativily in Python 2 and 3.
Remove any messing with builtins
Fix an issue I was specifically having on Python 2.6.  I'm not sure why this hadn't come up before, except that maybe it's been fixed in newer 2.6.x versions...?
Fix a few stray Python 2-isms that crept in to new code since I first started this branch
This change to itersubclasses restores some determinism to it on Python 3.4.  See https://github.com/astropy/astropy/pull/1945#issuecomment-32522217

Conflicts:
	astropy/io/fits/util.py
Present a better warning about no .rst doctesting on Python 3
Fix importing argparse on Python 2.6
Merge pull request #1994 from mdboom/testing/better-warning-about-no-rst-on-py3

Present a better warning about no .rst doctesting on Python 3
Merge pull request #1301 from embray/fits-python-3

Remove io.fits dependence on 2to3
Merge pull request #1917 from mwcraig/fix-1761

Add len() to coordinates
Merge pull request #1915 from nden/error-fit-composite

Error fit composite