Fix OSS Audio and enable FreeBSD 11 support in Python 3.2 and 3.1

• Add the appropriate Python platform (plat-*) files for FreeBSD 11
• Update pkg-plist

Backport a upstream change [1] removing OS major version from the check
to enable the OSS Audio module in setup.py:

Issue #12326: don't test the major version of sys.platform Use
startswith, instead of ==, when testing sys.platform to support
new platforms like Linux 3 or OpenBSD 5. [2]

[1] http://hg.python.org/cpython/rev/50f1922bc1d5
[2] http://bugs.python.org/issue12326