The application is now single-window by default. The floating windows it
was composed of previously have all been docked in the main window.

Certain widgets (e.g. DataContainerInspectorWidget) may have to be
redesigned to better fit this new layout. Also, displaying multiple
rendering canvases at once is not supported yet.

git-svn-id: https://camplinux.in.tum.de/svn/campvis/branches/gui-redux@501 bb408c1c-ae56-11e1-83d9-df6b3e0c105e