This does the trick to fix the new issue that came up with #992.
Merge pull request #1121 from taldcroft/time-test-precision

Increase precision of time tests
Conflicts:

	astropy/time/tests/test_basic.py
Merge pull request #1118 from taldcroft/time-unix

Time conversion utc -> unix missing leap seconds handling
Update changelog in preparation for v0.2.3 release.

Conflicts:

	CHANGES.rst