Module: turtle

Bug nr. 1: 
   Phenomenology: The first pen constructed with Pen()
   has a different origin than all the next ones.
   
   Reason: Twofold. First, packing seems not to be
performed
   in time, so canvas.winfo_width() / height() do not 
   return the correct values.
   Second, canvas['width'] differs from
canvas.winfo_width()
   by 4. The same is the case with height. 
   
   Remedy (suggestions): 
   - call canvas.update() before calculation RawPen's
origin
   - in "emergency"-case set width to canvas["width"] + 4  
     (same with height)
     (Don't know if this value of 4 results from some inset
      or what ever ...)
    
Bug nr. 2:
   Phenomenology:
   circle doesn't update turtle-position (in case
tracer is on).
   Reason (and suggested remedy):     
   - self._draw_turtle() is missing at the end of
circle's code