Examples Cleanup

Some cleanup on builds, particularly rxjava-examples.

I can't add Scala support while retaining Groovy and have it work in Eclipse as the plugins collide. Gradle handles it fine for builds from command-line but editing via text editors and not IDEs is not ideal.

Perhaps the examples should go in the /src/test/ folder (or /src/examples/) of each of the rxjava-[language] projects instead of rxjava-examples?