First steps to ReactFX integration
Improve ReactFX integration with Scala

Unfortunately, the Scala compiler barfs with an unintelligible error...
Add new ReactFX Java version for Flight Booker
Add new ReactFX Scala version for Flight Booker
Add ReactFX Scala version for Temperature Converter
Add ReactFX Scala version for Timer
Add new ReactFX Java version for Timer
Add new ReactFX Java version for Circle Drawer
Add ReactFX Scala version for Circle Drawer