QtCreator framework

Initial project framework.

Produce the basic code in a subdir of Qt Quick3D which can build the plugin. The plugin should

• Create a special editor window when files of a recognized model type is opened using "File > Open..."
• The editor can also be activated from a menu item
• See the editor section of the attached tutorial
• For now it should just create the window, which is a a QGLWidget with nothing in it.