Changed to using better math to get rid of little imperfections in the results.

Changed to using better math to get rid of little imperfections in the results.
Rather than create a rect and rotate it, create the rect in place using the exact values of the coincident points.

Add / subtract the circles seperatly because adding them to the rects leads to imprecise (because of floating point) intersections, leading to non-coincident edges again.