Vase cover (swing)

This creates a cover for a flower vase, so the flowers will be more upright.

This is my first scad project, so changes can occur.

This design can be changed using the parameters:
- detail: the number of segments the used to create the circles
- nofCircles: the number of circles used to create the inside
- height: height of the cover
- borderheigth: the extra height of the small border
- borderwidth: the width of the small border
- outsidewidth: the width of the outer circle
- circleswidth: the width of the other circles