Updated Readme to specify that Maven 3 is required.

[ci skip]
Update README.md with required plugins for eclipse 3.7
Change name in base pom and version

End the version name craziness and go back to have 0.4-SNAPSHOT as
version number. Also change the name of the toplevel pom back to
stratosphere.
Changed branch handling logic to correctly recognize disjoint data flow graphs, rather then erroring out.
Fixed erroneous costs handling in sink joiner.
Fixed wrong URL of quickstart script in README file.
[ci skip]
Fix stratosphere-dist to include the scala jars

Also fix an annoying bug that made tests fail because a dependency on
scala-reflect was wrongly in the "test" scope and also add an example of
how to create a PlanAssembler for a scala job in WordCount