Removed debugging print statement
Merge pull request #1517 from astrofrog/minor-warnings-fix

Minor warnings fix
Removed more debug print statements
Merge pull request #1526 from astrofrog/nddata-stats-time-six

Refactor astropy.nddata, astropy.stats, and astropy.time to use six instead of 2to3
Attempts to fix
Add table of built-in cosmologies, other minor documentation cleanups.

* closes #1147
Remove debugging print statements
Merge pull request #1510 from mdboom/tests/six

Update astropy.tests to use six instead of 2to3
Remove table.cols, unneeded comments, unneeded DictLikeNmy
remove index for columns - since all columns are always there, no separate index is needed
remove leftover comment
add tests for array separations
Merge pull request #1513 from mdboom/config/six

Update astropy.config to use six instead of 2to3
Use anonymous references to six
Fix sphinx warning, add note about doc update

* Extra space before code block in Built-in Cosmologies section
  of index.rst
* Add warning to parameters.py to update the documentation table
  when adding a new cosmology
Put the astropy.wcs include headers under its own directory so they
aren't confused with other headers at the top-level (notably sip.h from PyQt).
Merge pull request #1528 from mdboom/wcs/include-in-subdirectory

unknown type name 'sip_t' [Xcode 5]
removed use of removed make_kernel from test_convolve_speeds.py

pointed out by @cdeil in #1509
change the way null values are handled in IPAC table writing

fixes #1344
add strip to remove extra whitespace in python3