add block handler to handle block files on different under file systems
add BlockHandlerHdfs as stub
Trying to fix HBase support issue in TACHYON-27
change isHadoopUnderFS() in UnderFileSystem to be public, and use it in BlockHandler
modify comment format and gramma mistakes
some format fix
Optimize imports; reformat code style; improve javadoc; remove the commented code.
Linked to TACHYON-46 in Javadoc
Improve Javadoc comments
Merge branch 'master' of https://github.com/amplab/tachyon into createNonRecursive
createNonRecursive() should throw exception if parent directory doesn't already exist,  which is extremely important for HBase to do fencing of dead region servers properly.
[TACHYON-65] Fix the listFiles method

[TACHYON-65] the ListFiles(path,recursive) function of
tachyon.master.MasterInfo class does not work well
Include webapp dir in tar
Merge pull request #351 from dcapwell/assembly-war

Include webapp dir in tar
log stack traces on error and keep error history
modify according to the comments, format change
fix typo
change error message
Merge pull request #352 from dcapwell/client-stacktrace

log stack traces on error and keep error history
Merge pull request #349 from shimingfei/TachyonFileFix

modify retrieveByteBufferFromRemoteMachine in TachyonFile.java according to RemoteBlockInStream.java