HV-878 Integrating Optional and JavaFX types

You're right. I'll rewrite it in two different routines, one for parameterized types, and one for non-parameterized types.

> I just had a quick look at the type hierarchy of JavaFX properties, and it seems as if we should actually have an unwrapper for ObservableValue which is the upmost type in the hierachy which wraps a value. WDYT?

I'm trying to the limit the possible range of types supported by the annotation. `ObservableValue` has dozens of subtypes which are not properties. This can confuse the user and will make annotation processor checking more difficult. Any advantage is using `ObservableValue` as compared to `ReadOnlyProperty`?