As per #101, Memcache has some issues with the values in cache.
Added a basic test for some other values that crossed my mind but then I discovered that there are even more problems. Hence I've hacked the memcache part so ugly. I'm not proud of it but if you want to merge this without that part let me know as I'll remove it asap. It's 2 AM here @ time of this PR.
Also while running the tests I've created I've noticed that Memcached a similar issue and since I've noticed that we don't do any clean-up for the tests I've added the tearDown() function that should solve it.
Again, I'm not proud of how I did the memcache part so if anyone comes up with better ideas let me know and I'll update this. Also if you want to merge this PR without the memcache ugly hack, let me know and I'll remove it asap.
Improved memcache(d) drivers plus some clean-up
Since I could run only part of the tests for cache, APC, Array, Memcache(d), could anyone else using the rest, confirm that the tests are still passing? I'm clueless about the rest of the drivers.