Http: Java Routing API Preview

Here's the first batch of the high-level Java server API which already demonstrates a few concepts. Looking at the examples already explains much but I will write a summary as we go along as well.

Implementation is also already available (https://github.com/spray/akka/tree/w/15911-java-routing-dsl-implementation) for everything demonstrated here but omitted here for clarity.

/cc @sirthias 
Yes, of course, the last time I looked it was still missing from Ubuntu 14.04 but it seems it has come to 14.10 and will sooner or later be backported to 14.04 as well.

What's the path in OSX?