created self.warnings outside except block
Fixes #725. Moved the cython_version.py generation until after the normal build_ext command runs.  There was really no specific reason for it to go first.  Also check to ensure that the build/lib directory exists yet before doing anything with it.
Add initial infrastructure for io.ascii meta handling
Update DAOphot reader to use new meta infrastructure
Parse IPAC table metadata (keywords and comments)
Fix mistake in IPAC reader docstring
Improve DAOphot and IPAC reader docstrings
Improve the CDS reader doc string regarding metadata
Update IPAC docstring to fix an error in sphinx build
Make IPAC and DAOphot examples work literally and show output
When downloading a file, and we know it's size from the header, check that the temp filesystem and, if necessary, the cache filesystem have enough space before beginning the download.
Remove io.ascii doc references to non-existent NumpyOutputter
Add SI prefixes to arcsecond
Get a better error message when conflicting units are defined.
Delete the temporary file if a download fails or is interrupted
Merge pull request #874 from taldcroft/ascii-doc-fix

Remove io.ascii doc references to non-existent NumpyOutputter
Fix #863, that degree is not a base in SI
Merge pull request #831 from eteq/fix-automodsumm-warning

automodsumm: created self.warnings at start of run
Add TimeAstropyTime format to instantiate from list of Times
Merge pull request #858 from mdboom/utils/check-file-size-before-download

Check free space before downloading a file