Spark SQL based Shark CLI

Merged PR #337 authored by @chenghao-intel, and then did some refactoring and update, mainly include:

- Minimized `CatalystContext` as we don't care about response code for now, should update after [SPARK-2106](https://issues.apache.org/jira/browse/SPARK-2106) is addressed.
- `CatalystDriver.destroy` should call `super.destroy`.
- A bunch of trivial coding style fix (including original Shark code).
Thanks, the Spark SQL branch is changing somewhat rapidly, and I'd like to update the README file when it's somewhat stabilized :)