[FLINK-1325] [streaming] Added clousure cleaning to streaming

This closes #273
Fix invalid type hierarchy creation by Pojo logic
[FLINK-610] Replace Avro by Kryo as the GenericType serializer

The performance of data-intensive jobs using Kryo is probably going to be slow.

Set correct classloader

try to use Kryo.copy() with fallback to serialization copy
[FLINK-1333] Fixed getter/setter recognition for POJOs

This closes #271
[streaming] StreamInvokable rework for simpler logic and easier use
[scala] [streaming] Base functionality added for streaming scala api
[scala] [streaming] Extended scala data stream functionality to include simple operators
[scala] [streaming] Finished scala StreamExecutionEnvrionment functionality + DataStream sinks + docs
[scala] [streaming] Windowing functionality added to scala api
[scala] [streaming] Added SplitDataStream functionality

Conflicts:
	flink-scala/src/main/scala/org/apache/flink/api/scala/streaming/DataStream.scala
[scala] [streaming] Added support for iterative streams for scala api