Updated scala version to 2.13.4
Compiles to Java 11 now
Updated sbt to 1.4.3
Updated scalafx version to 14
Removed unneeded dependencies
Removed Akka code
Added lint and fatal warnings scalac options
Added parantheses to side effecting methods
Added >> and << methods to observables
The custom region doesn't quite work yet, so just expose the underling
bar so we can still get the shared behavior. Maybe the region will get
fixed later on.
JavaFX & ScalaFX already have one of these, but this handles padding
and automatically set up the apply, ok, cancel trilogy (though you can
disable any of these).