Stagetester

This merge would add a first version of my StageTester, allowing to test single stages within JUnit test cases.

See merge request !29

Distributor clone strategy

This merge would add an experimental implementation for the clone strategy of the distributor. It tries to create a new instance of incoming elements and uses available getters/setters to copy the values. Technically it is not a deep copy and I doubt it to be very fast. The additional JUnit test documents the functionality.

See merge request !30

added RunnableConsumerStageTest

added setter to Iterable- and InitialElementProducer

Benchmark

Contains:

* the benchmark, as discussed
* a test for the benchmark (without testing data loss)
* a protected static method in CompositeStage, to connect stages
* final declaration of all classes
* signal-bug fix in Merger
* new images in the download page
* EveryXthPrinter extends CompositeStage
* moved util.test

See merge request !28

Conflicts:
	src/main/java/teetime/framework/RunnableConsumerStage.java
	src/site/markdown/wiki

can't be modified to always run perfectly

enhanced the docs for the benchmark so it can be used as example or for
demonstration

test still not working 100%

added list of words and their number of occurrence

set to the CompositeStage's thread;
first scaling test prototype

prototype works correctly, still no scaling

renamed DistributedMapCounter to MappingCounter;
added first draft of WordCounter

consumption);
added CountingMapMerger, see JavaDoc