implemented RiakCache.
Implemented support for flushAll as per php_riak 0.5.0 release (to happen yet on PECL). Still no support for HEAD operations (contains()).
Updated RiakCache to match version PECL riak 0.5 release.
Added automatic conflict resolution.
Documented conflict resolution logic for internal.
Merge pull request #11 from doctrine/RiakCache

Implemented RiakCache.