Allow time format and scale strings to be case-insensitive
explicitly stated that we follow the PSF code of conduct
Attempt to fix #1179.  Test failing on Debian/MIPS because of an errant floating point warning
Add documentation describing Planck13 and massless neutrinos
If an IOError or ValueError occur when trying to check if the 'header' variable is a valid pathname then go ahead and assume it is not a pathname
fix bug in writing AASTex tables

The old implementation did not honor `latexdict['tabletype']` for AASTex tables
due to the order in which the various defaults were set.
This fix restores that and makes it possible to write e.g. 2-column
deluxetable* tables.
Small changes in existing tests are sufficient to make sure this bug will not
creep in again.
Fix #1374: `to_string()` should return a real string when it is a scalar.
Units now allow complex values
My fix for issue #966
Moved code to where it belongs.
Somehow it got left in the old place, so the bug was still occurring.
Added test for add_row() failures.
Raise an ImportError rather than call sys.exit() when astropy can't be imported from a source checkout; also add a _teardown_log function to undo Astropy's logging setup--otherwise subsequent attempts to 'import astropy' in the same session lead to strange exceptions.
Modified the spherical distances with NumPy

The spherical distances functions are now NumPy dependent. They no
longer depend on Python's math library.
Fixed code to pass test

lat and lon input variables were placed in the wrong order.
Fix a typo (which never came up due to the except: pass) and add the PR number to the changelog.
Restore the original log level after each of these tests; this still didn't solve the issue but it seems worthwhile
Fixes the tests in question by not assuming that the default log level is INFO
Define degree, arcmin and arcsec Unicode characters in the latex preamble
Fix docstring format in astropy.modeling.polynomial.Legendre1DModel.deriv
provided indications to build the PDF documentation