Display state of mesh boundary edges now stored in GLViewer and controlled by toolbar buttons in UIMainWindow.

Shading model state (flat or smooth) now stored in GLViewer and controlled by toolbar buttons in UIMainWindow.

Bug fixed in the import of a file when no project exists and the user presses the "Cancel" button in the "New project" dialog box.

Bug fixed in the reinitialization of the GLViewer when a project is created/opened or when the last project has been closed.

Callback mechanism added to capture modifications in the parent relationship by drag and drop events.

Widget stack modified so as to make it possible to split the screen in two and to keep the previous widget in one of the two sub-windows.

Bug related to the conflict between the deletions of UIData and GLViewer solved by the mean of Qt signal/slot mechanism.

Stack mechanism added to UIMainWindow in order to change its central widget by saving and restoring the previous one.

Callback function added to UIMainWindow to trigger events when the selection in the project view changes.

Creation / loading / switch from one to another / closing.
Project saving is still missing.

Item tree widget now makes it possible to switch on/off the display of multiple items at once, by checking/unchecking an item included into a multi-selection.

ToolCategory mechanism modified so that user can declare on the fly during application initialization its own categories.