rem: WMSetRulerOffset(WMRuler *rPtr, int pixels)
add: void WMSetRulerOffset(WMRuler * rPtr, int pixels)
context: WMSetRulerOffset(WMRuler *rPtr, int pixels){    if(!rPtr || pixels<0 || pixels+MIN_DOC_WIDTH>=rPtr->view->size.width)        return;    rPtr->offset = pixels;    /*rulerDidResize(rPtr, rPtr->view);*/}