[FLINK-701] Refactor Java API to use SAM interfaces. Introduce RichFunction stubs for all UDFs.
[FLINK-701] Several cleanups after SAM refactoring.
  - Lambda detection compiles on earlier java versions
  - Add lambda detection test.
  - Fix JavaDocs
[FLINK-701] Change KeySelector to a SAM interface

This closes #85
[FLINK-1023] Switch group-at-a-time function to java.lang.Iterable (from java.util.Iterator)
Iterables over transient data throw an TraversableOnceException when iterated over again.

This closes #84
[doku] fix broken image urls
Create release scripts, add support for "cdh4" build.
Reflect recent changes to Java API documentation

change text to String

This closes #87.
[FLINK-909]  Remove additional empty (and non empty for iterative broadcast variables) superstep.
[FLINK-945]  Fix early memory release in iterations
[FLINK-909] Adjust aggregators test case
Disable POJO types

There are various issues when working with POJOs in the Java API, for
example [1].

This commit squashes the following commmits:

1. Disable tests, which depend on POJO types

2. Replace expression keys with key selector in test

3. PackagedProgramEndToEndITCase used a KMeans variant, which relies on
expression keys to select the field to group on. This commit replaces
this with a key selector.

4. Disable WordCountPOJO test case and package

5. Disables WordCountPOJOITCase, which executes the WordCountPOJO example.
The example code is still included with the source code (with notice
that it is currently not working), but will *not* be packaged as a JAR
anymore.

6. Disable tests, which depend on POJO types (continued)

[1] https://mail-archives.apache.org/mod_mbox/incubator-flink-dev/201407.mbox/%3C53D96049.1060509%40cse.uta.edu%3E

This closes #93.
Remove expression key methods
Fix broken history due to misplaced google load js
Extended release script, update nightly build script