Python 3.4 failures

I got a [report](http://bugs.debian.org/734293) that astropy fails to build and tested on python-3.4. The issues are:

1. astropy/logger.py: logging._levelNames does not exist anymore

 This can be fixed with [a simple patch](http://launchpadlibrarian.net/161653497/python-astropy_0.3-4build1_0.3-4ubuntu1.diff.gz).

2. With this patch, the following tests failed:

 * astropy/cosmology/tests/test_cosmology.py:94: test_repr
 * stropy/nddata/tests/test_flag_collection.py:43: test_setitem_invalid_shape
 * astropy/table/tests/test_operations.py:266: TestJoin.test_rename_conflict
 * stropy/vo/validator/tests/test_validate.py:135: TestConeSearchResults.test_printcat

I couldn't see a particular pattern in the failures. See [full build log](https://launchpadlibrarian.net/161654270/buildlog_ubuntu-trusty-amd64.python-astropy_0.3-4ubuntu1_FAILEDTOBUILD.txt.gz).