the error message is QML itself, coming from the Corona package (so there is the possibility that even the error message can't parse, in this case we have no way to show an error)
the user of the qml plasmoid still can't set a message on his own (setFailedToLaunch will probably become scriptengine only)
AppletInterface is a QQuickItem ans
containments will receive pointers to AppletInterface as applets,
so will be able to have a limited access to it.
as an example of it working the button in the example applet enables/disables background hints
I'm still not 100% happy about it, we should see exactly what it happens when the containment deletes the graphic object.
