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.

Also make alle the examples that work implement PlanAssembler and output
generated example jars for these examples to examples/pact-scala in the
distribution.
Merge pull request #179 from aljoscha/fix-scala-jars

Fix stratosphere-dist to include the scala jars