When a model is loaded and one or more catalogs needed for being able to reconstruct
assemblies are not present, Experior will automatically load the catalogs if the file exists
and you have to have the right privileges to load it, otherwise you will be informed.
Ticket #252 fixed.
The use of the shift key has changed.
In earlier versions, the shift key were used to change the center of the model but that is
not a very familiar behavior (the center of the model were changed just by pointing and
clicking the left mouse button without selecting any objects).
In this and future versions you have to draw an area by holding down the shift key while
dragging the mouse: when releasing the mouse button and the shift key the view is then
changed according to the size of the area.