Removed unnecessary factor of 10
Added distance function
Improved accuracy of intersection

 - Did not align very well with mouse because I was using a big formula
   for r, but once I have x and y, r just needs to be the distance to the
   mouse pointer. Now much more accurate, but still gets off when the
   radius is far away. Maybe look into my own circle drawing algorithm to
   improve this.
Removed optional clockwise arc parameter
minor html/css improvements