replace modelviewer "Model" menu with "View"

The "Model" menu contains a number of built-in models, but we probably only need one to be displayed by default the first time, leaving other models for "Open". I suggest to use the trolltech-q as the default for the first time it is launched. Perhaps replace "Model" with a "View" menu that has menu item versions of Top/Left/etc? Zoom should probably move to "View" also.