Java 9 and TestFX4

[tbeernot]

I've started migrating JFXtras to Java 9. But prior to that we needed to upgrade TestFX to 4.x, because its Java 9 migration will be done on the 4 branch. I've decided to add some immediately deprecated methods to JFXtrasGuiTest to batch-fix a lot of test; many of the errors are caused by method renaming in TestFX (e.g. click -> clickOn, type -> write). In time these methods are to be phased out.

Most of the test are running again except icalendaragenda. @David, would you mind picking those up?

Tom