[gtkmm] Updating a custom TreeModel

[Tor Arvid Lund <tor arvid lund idi ntnu no>]

Hello,

I have made a custom TreeModel from the treemodelcustom example/demo 
application that comes with gtkmm. My TreeModel uses a std::vector to 
hold its data, just like in the example. But my vector starts out empty, 
and items are added/removed dynamically.

The TreeView associated with the Custom TreeModel will always show the 
first row in the vector, so my question is: How do I tell the TreeModel 
that new data is available in the vector?

Regards,
Tor Arvid Lund