Updated maven build configuration for Scala 2.10

HttpBroadcast server cache by default in spark.local.dir instead of java.io.tmpdir

remove unused thread pool

Generate FetchFailedException even for cached missing map outputs

Updated SCALA_VERSION in run2.cmd to match runtime version of Scala

Changed teh scala version to 2.9.2, so that the classes can be found when the classpath is expanded.

Scala 2.10.0

Call executeOnCompleteCallbacks in a finally block.

- akka  2.0.3  → 2.1.0
- spray 1.0-M1 → 1.1-M7
For now the repl subproject is commented out, as scala reflection api changed very much since the introduction of macros.

Changed CoGroupRDD's hash map from Scala to Java.

Add missing dependency spray-json to Maven build

Python API (PySpark)

fix spelling mistake in LocalLR example

fix spelling mistake

Executor and JobDescription JSON support added