HEX-600, HEX-596 & jython scavenging
Switched JUnit to Java only & added EC2 util
Merge branch 'junit_ec2'

Conflicts:
	build.sh
	src/main/java/water/Log.java
	src/main/java/water/TypeMap.java
	src/main/java/water/store/s3/PersistS3.java