[SPARK-2399] Add support for LZ4 compression.

Based on Greg Bowyer's patch from JIRA https://issues.apache.org/jira/browse/SPARK-2399

Author: Reynold Xin <rxin@apache.org>

Closes #1416 from rxin/lz4 and squashes the following commits:

6c8fefe [Reynold Xin] Fixed typo.
8a14d38 [Reynold Xin] [SPARK-2399] Add support for LZ4 compression.