Add check for NPE.
Cosmetics: make hdfs, s3, nfs upper-case.
PUB-610: Add ExportFiles to write VA and FVecs to HDFS and local file system.
Merge branch 'master' of https://github.com/0xdata/h2o
PUB-610: Add a force flag to allow overwriting existing files.
Merge branch 'master' of https://github.com/0xdata/h2o

Conflicts:
	src/main/java/water/api/Inspect2.java
	src/main/java/water/api/RequestServer.java