Globally configurable default modes for overwrite / output directory behavior.
Configurable behavior for FileOutputFormat through regular parameters, rather than configuration.

File paths used as default names.

Extend runtime for iterative algorithms.
Add iterative kmeans test for runtime code.

Allow cases where in-iteration DOP is lowered.

Extended FileOutputFormatTest.
Some code beautifications.

Rewrote code for file output path preparation.
Fixed distributed writing to local filesystem #286

This is a combination of commits:
* make hadoop-compat compatible to hadoop yarn and remove org.apache.hadoop code
* Extended usercode wrapper, fixed IF serialization
* introduce pluggable type converter
* make the converter interface more generic; (hopefully) improved fetching logic

disable javadocs gen when java6 is being used.

Fixed doc warnings for MemorySegment

fix yarn copyright
adopted hadoop configuration for hadoop 2.2.0

Add accumulators to web interface

Conflicts:
	stratosphere-core/src/main/java/eu/stratosphere/configuration/ConfigConstants.java
	README.md

WorksetIteration changed to DeltaIteration.