Retransform Refactoring

Preventing doing retransformScale(-1, -1) on all ranges, only on the needed once. Do not update the datarect if it did not change.

• remove retransformscale() it must not be done every time. Only when the ranges change and initially (increase of speed)
• fixes #62 (closed) Unittest written
• Check dirty. If autoscaley not always xrange shall get dirty. Performance improvement because when doing an action multiple times, the xrange will not be recalculated every time
• fixes #226 (closed) (unittest covered)
• Check that updateLines is really called