Added Memcache class.
Added test cases of Memcache class.
Rename Memcache.php to MemcacheClass.php because of the name conflict of the namespace Memcache.
Updated Memcache Class.
Updated test cases of Memcache class.
Added more Memcache test cases of Cache class.
Cleaned File Cache class.
Updated config and namespace for Memcache.
Updated getObject function in Cache class. It can now return singleton object for Default cache or Memcache.
Large updated about Memcached. More clean up are needed.
Updated getObject() in Cache class.
Updated test cases of Memcached.
Added more comment blocks to Memcached class.
Updated Memcached class and its test cases. Added a getObject function in Memcached class, so that users can directly use the Memcached object to call its methods.
Updated Memcached test cases in CacheTest.php
Added comment blocks for test cases of Theme class.