Changed operation of loading/saving of calibration files. A folder with the name of the configuration serves as the starting point. Each projector has its own subfolder (with the name of the projector) to save its data into. Loading does not open a dialog anymore, location to load from is known from the specified configuration. Optimized render-mode in setup-mode: only compute the calibration of the view that is being calibrated (if we continuously do this for all views, framerate drops to 1 fps if the calibration is not very precise). Also: also only draw the view to calibrate in this mode, not the other ones: we don't want to other projectors shining light onto the shape while we are doing this.