JPro support

[FlorianKirmaier]

Nice to see rich text getting done!
Dirk asked me to check whether everything works with JPro and point out possible issues.

There are some minors:

• showAndWait, JPro doesn't support this, and in general, I have made a very bad experience, with all the thread magic showAndWait does. Can you somehow change this in a way, that only show is used?
• Windows without owner, If the owner would be set, JPro would properly display it to the correct user.

And the big topic, TextSupport
JPro currently has a hidden Textfield, in the browser, which gets synced with the currently focused element.
This is done, when an Node of the Type TextInputControl is used.
Would it be possible to implement this class?
Alternatively, it would be possible, if we provide an interface, with the parts of TextInputControl, that we need need to make this work.

You might wonder, text worked when we tested it. JPro created KeyEvents which work properly often, but not always. But the Keycode etc. are very OS and browser dependent, which makes this very unreliable. Java and Swing Keycode also have their one complexity. CopyPaste also doesn't work - it only might seem like it, because the client is running on the same device as the server - which has the effect that they share the same clipboard.