[streaming] Change 'getParallelism()' signature to return a primitive to avoid failed equality checks.

  1. TDD reception with eager acknowledgement and
  2. TDD instantiation with a subsequent state update message.

This closes #622

[FLINK-1923] [runtime] Replaces asynchronous logging with synchronous logging using grizzled-slf4j wrapper for Scala.

This closes #628

This closes #631

[yarn] [python] Adds -Xms start option for yarn, fixes python test case to overwrite files, fixes python docs

Fixes failing yarn test cases

This closes #637

This closes #35

This closes #632
This closes #571

FLINK-1693 Add DEPRECATED annotations in Spargel APIs and update the doc to refer to Gelly for Flink graph processing.

Mark all user-facing from the Spargel API as deprecated and add a comment in the docs and point people to Gelly.

This should help migration to Gelly in the next release.

Author: hsaputra <hsaputra@apache.org>

Closes #618 from hsaputra/FLINK-1693_deprecate_spargel_apis and squashes the following commits:

4652805 [hsaputra] FLINK-1693 Add DEPRECATED annotations in Spargel APIs and update the doc to refer to Gelly for Flink graph processing.

- code formatting
- simpler python process initialization
- renaming of the python connection following the switch to TCP

This closes #616.

This closes #617.

The problem: when a pipelined result is only consumed partially, the buffer pool
associated with the result partition will be destroyed too early. If there is a
pipelined producer online, which is still producing data for this partition, it
will run into an IllegalStateException.

The solution: by separating the life-cycle of the result partition and the
associated buffer pool this cannot happen anymore. The result buffer pool is
only destroyed after the producing task is finished, which is independent of
the state of the result partition.

Furthermore, this commit squashes the following commits:

- [FLINK-1930] [tests] Add test for FLINK-1930
- [tests] Move iterative tests to correct package

This closes #624.

Close the following unrelated PRs:

This closes #112.
This closes #134.

Due to the recent serialization changes.

This closes #576

[FLINK-1758] [gelly] made reduceOnEdges and reduceOnNeighbors only have accees to edge/vertex values, not IDs

This closes #408

improvements to the GSA Connected Components example

This closes #620