This closes #1327.

This closes #1343

[FLINK-2987] Remove jersey-core and jersey-client dependency exclusion to make Flink on Hadoop 2.6.0+ work

This closes #1340

This closes #1334.

This closes #1329

 - added auto-redirect for coding_guidelines and how_to_contribute pages (to keep external links working)
 - updated menu links to point directly to coding_guidelines and how_to_contribute on Flink project page
(only improvement on FLINK-2752; does not resolve it)

This closes #1320

The problem was, that truncate is asynchronous and the RollingSink was
not taking this into account.

Now it has a loop after the truncate call that waits until the file is
actually truncated.

This also changes the Hadoop 2.6 travis build to 2.7, instead.

* added libraries and versions

This closes #1335.

This closes #1315.

This closes #1333

This closes #1319.

[FLINK-2968] [streaming] Let AbstractUdfStreamOperator forward output type information to WindowFunction

The fold operation needs the output type information to serialize the
initial value of it. Therefore, the OutputTypeConfigurable interface was
defined. It is called by the StreamGraph upon adding a StreamOperator to
the StreamGraph. Since some stream operators, such as the window stream
operator, don't work directly on the data, but instead call a
WindowFunction for the actual logic, the output type information has to
be forwarded to this function to set output type information at the
right place.

Thus, the AbstractUdfStreamOperator checks whether its udf function
supports the OutputTypeConfigurable interface. If this is the case, then
it forwards the output type information to the udf.

This closes #1328.

This closes #1326

[hotfix][web-dashboard] Fix taskmanager charts legend.

This closes #1323

The HashPartition did not count properly the number of occupied memory
segments, because it excluded the memory segments of the
BuildSideBuffer. That caused the MutableHashTable to fail when trying to
spill a partition which did not have any overflow segments. This PR
fixes the problem by also counting the memory segments of the
BuildSideBuffer.

This closes #1324.

This closes #1299

- fix hard-coded defaults

This closes #1304.

This closes #1314.

The tool can be used to list the set of dependencies to make a diff
of dependencies between releases.

This closes #1313.

- Added tests for Scala DataSet sortPartition

This closes #1317.

This closes #1316.

- skip was only necessary because Java 8 couldn't build the java docs

- Prevents crashing of IntelliJ Checkstyle plugin