Fixed autosize, better display and better unit selection

src/main/java/plugins/tprovoost/scale/Scale.java

src/main/java/plugins/tprovoost/scale/ScaleBarLocation.java

src/main/java/plugins/tprovoost/scale/ScaleBarOverlay.java

src/main/java/plugins/tprovoost/scale/ScaleBarUnit.java

src/main/java/plugins/tprovoost/scale/ScalePainter.java

src/main/java/plugins/tprovoost/scale/ScalePainterOld.java