Add bindings that trigger changes on UI Thread

[tobiasdiez]

Background:
JavaFX requires that changes to controls are triggered on the UI thread. However, sometimes you have a binding that is updated on a different thread. In this case, the changes notification need to be passed to the UI thread.

Similar implementations:
https://github.com/JabRef/jabref/blob/master/src/main/java/org/jabref/gui/util/UiThreadList.java
https://github.com/JabRef/jabref/tree/master/src/main/java/org/jabref/gui/util/uithreadaware
https://github.com/griffon/griffon/tree/development/subprojects/griffon-javafx/src/main/java/griffon/javafx/beans/binding (uithreadaware bindings)