Enhancement : Lazy loading of editor pages

A backwards compatibility fix to ensure proper operation of editors
that override createModel() and possibly assume that it is called prior
to createFormPages() and createDiagramPages().

Bugzilla: https://bugs.eclipse.org/bugs/show_bug.cgi?id=444202
Enhancement : Lazy loading of editor pages

ReflectiveOperationException does not exit in Java 6.

Bugzilla: https://bugs.eclipse.org/bugs/show_bug.cgi?id=444202