Added support for SASL authentication in MemcachedCache, fixed FormParser bug, added support for python-binary-memcached

Support Additions:
- Memcached SASL auth
- Python binary memcached library

Bug fixes:
- Modified a FormParser test that was failing on account of a bad assertion
This test has changed since then to check for a specific attribute, because the Py3 port made type checking impossible. Please remove the fix.