Added regression test for Numpy bug in Python 3 prior to Numpy 1.6.2
Add a known issue for the sorting in Python 3 with old versions of Numpy
Skip Table.sort tests that fail in MacOS X with Python 3 and Numpy < 1.6.2
Merge pull request #1671 from astrofrog/sorting-failure-py3

``Table.sort`` failing on MacOS X