Integration of new BLOB service.

Looped through the user code class loader from the envrionment to the tasks.

Added timed cleanup task to LibraryCacheManager to remove automatically unreferenced jar files. Moved registration logic out of the IOReadableWritable serialization logic. Updated logger.

Made the LibraryCacheManager an object instead of a Singleton.

Added proper shutdown of task manager and job manager.

Removed nio import to support Java 6 compilation.

Removed lock map from BlobLibraryCacheManager. Using global lock for synchronization. Marked StackOverflow code. Removed JavaDocs copyright message. Added getUserCodeClassLoader to AbstractInvokable class.

This closes #126 and closes #107.
[FLINK-1139] Added FinalizeOnMaster hook to run code after the last task of an OutputFormat completed
[FLINK-1139] Fixed HadoopOutputFormat to run with DOP > 1