Should not overwrite previous $CLASSPATH

Minor change to pom.xml file
(cherry picked from commit afecdfc)

Minor change to pom.xml file

made examples callable and added the error handling to a function

format

change path in StorageDir from String to TachyonURI
rename WorkerSpaceCounter to SpaceCounter
Merge pull request #463 from pfxuan/maven

Minor change to pom.xml file
Merge pull request #470 from shimingfei/RenameWorkerSpaceCounter-new

rename WorkerSpaceCounter to SpaceCounter