title: Raphael end of line follows cursor
body: <p>Note: this question is similar to a few others, but I've had trouble extracting the central logic from the answers. </p>
  
  <p>I'm trying to do the following: a user can click the page, anchoring one end of a line. Eventually, she will click again to anchor the other end. In the meantime, though the second line end should float with the cursor, thereby showing what the final line would like at any point. </p>
  
  <p>I believe the solution will involve mousemove(), but I haven't been able to find a simple example showing how this works. </p>