Adding Lz4 Codec.

Change-Id: I29d6ccc5b62eff42b74d92bc9af7348b6bec2cef
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2948
Reviewed-by: Paden Tomasello <paden.tomasello@cloudera.com>
Tested-by: jenkins