Rendering now only happens when necessary. Not smooth.

The plan is to now transition into using scale transforms
instead of re-calculating the d0 each time. This should
provide significant speed improvements
This is what a lock-scale button would look like. Good idea.
Using transform scale instead of re-drawing!

Normal zooming works perfectly. It's fast on firefox!
Will have to re-do the scale on each level change
so that it doesn't keep scaling in the x axis and get ugly.