[streaming] DataStream print functionality update

PrintSinkFunction now explicitly states threads in output
Added printToErr functionality
[streaming] [examples] Refactor and packaging for windowing examples

The current examples show-case the API, more meaningful examples are coming for the 0.9 release.
[streaming] Updated deprecated iterative functionality and docs
[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