Added missing assignment operator, fixed autoDraw and autoUpdate, added option to remove header widgets.

- Added missing assignment operator to ofxUISuperCanvas
- Moved autoDraw and autoUpdate options out of ofxUICanvas and into ofxUIAppCBGlue where it is now working
- Added option to disable and remove header widgets in ofxUISuperCanvas by:


    ofxUISuperCanvas::setUseHeader(false);

where

    ofxUISuperCanvas::setUseHeader(true);

will add the title back again.