- The Rose diagram coordinate system is roughly twice the scale of Qt.
  I.e. when going from Rose diagram-object location/width/height to Qt,
  we need to shrink everything.
  New constant Rose2Qt lets use configure the exact factor.
- In function fetchLocation(),
  - add missing "return" at case !ok;
  - multiply `x' and `y' by Rose2Qt on constructing QPointF() return value.
- In function fetchDouble(), multiply value by Rose2Qt on returning.
- In function umbrellify(), declare `width' and `height' before start of
  for-loop over `atts'. Reason: Rose diagram locations denote the object
  CENTER thus on seeing a "location",
  - for X we must subtract width/2
  - for Y we must subtract height/2