`.cache` is generated when unittests are run with py.test

This commit also alphabetizes the distribution/packaging section after
separating the directory entries from the file entries.  I left alone
a few entries that I'm not sure about (i.e. *.egg and the
"Mr Developer" section).

Commenting the only ignore that isn't commented.

nosetests.xml is created by the 'nose' test runner when you want xml output, for instance for integration with jenkins.