Updated Nephele task names.
- Names have prefix of Pact contract (Map, Red, Cmb, Mat, Crs, CGp, ...)
- All chained tasks are added to name of chain parent
Extended task names
Merge branch 'taskNames' of https://github.com/fhueske/stratosphere into fabian

Conflicts:
	pact/pact-compiler/src/main/java/eu/stratosphere/pact/compiler/plan/WorksetIterationNode.java
Added integration test case for AllReducer and iterations