Displays the receiver and begins its event loop.
Original signature is '- (NSInteger) runSetupPanel'
Returns NSOKButton (if the user clicks the default button) or NSCancelButton (if the user clicks the Cancel button).
- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)