|#102 Scala verticle factory now tries to load different class names

* This helps better support situations when the system path to the
scala source file is provided. The code now recursively tries to find
a valid class name given the path.
* Refactored the ScalaVerticleFactory code and ScalaInterpreter to
make sure of Try/Success/Failure in order to better manage unexpected
situations.
* Updated to Vert.x core release 2.1-M2