Zeppelin 26

[cfmcgrady]

Base on this branch(https://github.com/Leemoonsoo/incubator-zeppelin/tree/ZEPPELIN-26). add HDFSNotebookRepo.

[Leemoonsoo]

Hi, @cfmcgrady. Thanks for contribution.

Constructor type for NotebookRepo is slightly changed.
from NotebookRepo(ZeppelinConfiguration conf, URI uri) to NotebookRepo(ZeppelinConfiguration conf). Please rebase this branch with master branch.

One concern is
Currently zeppelin-daemon process and interpreter process uses common.sh to construct it's classpath.
Once zeppelin-daemon have HDFS dependencies, then by common.sh, it'll be also loaded into every interpreter process. Especially spark include HDFS related dependency, too, they'll conflict.

And version of HDFS related dependency's is fixed. i think it'll be better if it is configurable.

[cfmcgrady]

@Leemoonsoo.
so which is better way make version of HDFS configurable.

[Leemoonsoo]

@cfmcgrady I think using maven property is an option for making HDFS version configurable. For example spark interpreter is already doing it.

[jongyoul]

@cfmcgrady Do you have any update for this? Otherwise, Could you please close this PR?

[corneadoug]

@cfmcgrady Is this PR still relevant?
Otherwise I will close it