ZEPPELIN-45: Integrate Tajo with Zeppelin

[blrunner]

I succeed to test on local tajo cluster and distributed tajo cluster and I borrowed some classes from apache commons dbcp2 for unit test implementation.

Please see following site.
https://issues.apache.org/jira/browse/ZEPPELIN-45

[Leemoonsoo]

Thanks for the contribution!
Let me test this.

[Leemoonsoo]

Tested and works well.
One more thing is, could you add TajoInterpreter class to the default configuration in ZeppelinConfiguration? line 383, ZEPPELIN_INTERPRETERS property.
This values are used when zeppelin-site.xml is not exists.

[blrunner]

Hi @Leemoonsoo

Thanks for your review. I've updated this as follows.

• Added this to ZeppelinConfiguration for default configuration.
• Updated Tajo builder order because it had caused a problem to ProtocolBuffer dependency.
• Updated ZeppelinRestApiTest::getAvailableInterpreters

And if you authorize me to assign JIRA issue, it would be better for me to contribute Zeppelin continuously.

Cheers
Jaehwa

[blrunner]

I found that ProtocolBuffer wrong version had been downloaded occasionally. I'm digging this.

[blrunner]

I fixed a bug about protobuf version.

[Leemoonsoo]

Looks good to me!