Tweak contour intersection demos

1. Change size of circles indicating intersections
to make it obvious that the circles are not filled,
and that only part of the intersecting shapes are
being drawn.

2. Make intersecting shapes more visible by using
different colors.

3. Animate self-intersecting shape.

openrndr-demos/src/demo/kotlin/DemoContourIntersections01.kt

@@ -29,7 +29,7 @@ fun main() {
                     }
                 }
                 for (i in ints) {
-                    drawer.circle(i.position, 15.0)
+                    drawer.circle(i.position, 10.0)
                 }
             }
         }