SWT-JFace dependency unnecessary

[fab|an]

Hi,

 the only use of the jface package in swt at the moment in the class ILabelProvider which provides data for things like EventComboViewer. The problem I see with this, is that this one class requires an entire new jar for your application. Since ILabelProvider is not even generic/typesafe I'd suggest adding a LabelFormat class to GL.

Sincerely
Fabian