Add optional --delete flag to copy-dir.
Merge pull request #26 from pwendell/v2

Increase ulimit in spark-env.sh
Merge pull request #25 from JoshRosen/copy-dir-delete

Add optional --delete flag to copy-dir
add tachyon module
Merge pull request #28 from haoyuan/v2

add tachyon module
Add binaries for Spark 0.8.1