Added System and Experiment implementations for Spark.
Create README.md
Fixes for Spark.
Rename Stratosphere to Flink in README
Update README.md
Merge pull request #1 from rmetzger/patch-2

Update README.md
Merge pull request #7 from uce/patch-1

Rename Stratosphere to Flink in README
Added Flink, HDFS 2 extensions.

* Added support for Flink.
* Added support for HDFS 2.
* Renamed Hadoop 1 related files (added '*-1' suffix).
* Reorganized package structure.
Added support for generated datasets.
Updated peel-sketchbook scripts.
Fixes in the generated dataset logic.
Minor fixes:

* Proper exit on failed Job execute().
* Better error handling if system archive is missing.
* Added hadoop paths section in hadoop-env.sh for Hadoop 2.
* Simplified formatting logic for HDFS 2.
Core package improvements:

* Added sys:setup and sys:teardown commands.
* Fixed a bug in the DependencyGraph reverse method.
* Added 'app.path.downloads' parameter to reference.conf.
Added Zookeeper system.
Added Aura beans.
Cosmetic fixes in the reference.{system}.conf files.
Updated the sketchbook configs.
Teardown for redundant systems after materialization.
Removed redundant System object.
spark experiment fixes:
- gets event logs
- isUp is set to false when spark is stopped
- added expection to log msg
- minor fixes