Instead of using NetList or NetListPanel in annotations we introduce an interface AnnotationPanel (which is already implemented by NetList/NetListPanel).
Moving of annotations works!
Dragging of annotations should stop if mouse button is released. (Also edges are now again fixed after moving.)
Annotations now completely respect zoom level and Text annotations have a font.
Added `add` and `rm` methods for legends.
paint method for Line object.
Mathematics whether a given point is inside an ellipse or not (given by (x,y,width,height)).