Put jars for s.xml and s.u.parsing on classpath

As of Scala 2.11.0-M4, scala.xml and scala.util.parsing are
in [separate jars](https://github.com/scala/scala/issues/2704).

Improve `CompilerProvider` to deal with this in a backwards compatible way.
Merge pull request #22 from adriaanm/master

Put jars for scala.xml and scala.util.parsing on classpath for tests
Adapt test so it doesn't fail with the latest 2.11 PC.

Something fishy is going on here, the presentation compiler
complains about a type mismatch:

 found : Int => Int required: PartialFunction[Int,?]