No left= redraws

* As discussed in #871
* This was originally introduced in 8a35ebb to make sample 14
  work but it seems to work fine without, might have been
  misjudgement on my part or I'm missing something now
* It should work because the REAL repositioning on the GUI only
  happens through #_position which the slot positioning code calls.
  left= etc. just set values that are considered by the positioning
  code they should not have an effect by themselves
* includes styling changes for 80 character width


Adding those was misjudgement on my part, as the original PR states: _"sample14 leaves artifacts of ovals behind --> some area is not marked as damaged"_ but that was later on really solved by redrawing the old area before `_position` is executed and the new area after `_position` is called :-)

Should be good to go!