Pull upstream changes for WordPress Memcached Backend

Recent as of cb08739a7e in https://github.com/tollmanz/wordpress-memcached-backend/commit/cb08739a7edb43c87b6dac7b21528eaa94838a54
Merge pull request #59 from washingtonstateuniversity/object-cache

[PR] Pull upstream changes for WordPress Memcached Backend