[FLINK-1115] Local file streams retry file creation on FileNotFoundException to increase resilience against spurious failures in tests

[FLINK-1114] Move scala-style checks to scala projects, change paths to style conifg, to allow isolated building of individual projects.

Updated license notices in in java files to be written in block comments instead of javadoc comments.

Instead of waiting for the number of connected task managers, the local
mini cluster used for tests now waits for the total number of available
slots. Waiting for the number of connected task managers instead of the
available slots might result in races in rare situations.

In addition, rename task tracker (sic) to task manager in test classes.

Also convert to kramdown syntax

Was programming_guide.htmls

And create AggregateDataSet in the first place, to add the methods to.

This can now be built standalone and then copied into the correct docs
folder of the website SVN.

The index page now has a short overview and a table of contents.

Now contains Java and Scala examples with tabs to switch between the
two.

This now covers both Java and Scala.

The switch to kramdown is necessary because I want to add tabs in the
documentation for code examples and Redcarpet does not allow markup
inside divs.

Before, some doc pages had "#" headings as toplevel headings while
others had "##" (which is the same as --- underlined headings). Now we
user level 2 everywhere. The page title is still a h1 heading.

This better reflects what it is actually for. It is still derived
from TupleTypeInfoBase, though.

Also actually use termination criterion in TransitivelClosureNaive
Java example.

Add ConnectedComponentsITCase for Scala Example

Also fix some formatting in the example code

Add WebLogAnalysisITCase for Scala Example

Some minor reformatting of example code and scaladoc.

Add ITCases for TriangleEnumeration Scala Examples

Also fix some formatting and make TriangleEnumerationOpt Scala produce the
same output as the Java version.

Add PageRankITCase for Scala Example

Also fix formatting in PageRank Scala Example.

Fix formatting in EnumTriangles Scala Examples

Remove Old/Deprecated Scala Examples and ITCases

Fix formatting in EnumTrianglesBasic.scala

Fix formatting in LinearRegression Scala Example

Remove old Scala LineRank Code and RelQuery Example

[scala] Fix typo in scaladoc in GroupedDataSet

[scala] Fix Scaladoc of Join and CoGroup Operation

Was still referring to the type of join/coGroup function that returns an
Option.

Fix tab vs. spaces in flink-scala and flink-scala-examples

Some occurences in comments and POMs where not updated.

Also change signature of join and coGroup to always return a value, not
an Option.

This is very naive right now, just checks whether a function of the same
name is available. There are lists and regex patterns of excluded
functions since not all functions in the Java API need to be available
in the Scala API.

Fix join operator to user proper EquiJoin constructor so that semantic
properties are actually retrieved.

Fix typo, getSematicProperties -> getSemanticProperties

This does not change the runtime behavious. The key field names are
mapped to tuple indices at pre-flight time.

Also extends tests to cover the new feature.