Node handling + Fib database objects in choose dialog

The Fib node event where improved. They now contain the information, which
part of the Fib object changed. This was used to speed up the adaption for
Fib object changes. For example: Now just the graphical elements are
updated for which the Fib object changed.
(nFibNodeHandler::integrateFibObjectIntoNode() needs some more testcases,
see "add_ons/creator/testObjects/integrateFibObjectIntoNode/")

The Fib database objects are loaded into the select Fib object dialog (
cDialogSelectFibObject). Some changes also for better category and
selected Fib object info handling.

Some minor bugfixes and improvments