Update to work with 0.90.0

* Bumped the version
* The org.elasticsearch.common.Bytes class was removed from 0.90.0RC2 to 0.90.0
* The Bytes class has been simply copied into org.elasticsearch.memcached.common in order to avoid conflicts

Closes #10
prepare release elasticsearch-transport-memcached 1.5.0
prepare for next development iteration