Ported binary fractal tree from Elm to Helm

[Kaspar Emanuel]

Hey,

I ported the binary fractal tree from Elm to Helm, just to understand
some of the differences.

Elm: http://share-elm.com/sprout/53ee4e81e4b07afa6f9844c9

Helm: https://gist.github.com/kasbah/b6e638655f18c1e11a2c

As expected it is a lot smoother in Helm, though it also uses more
CPU. There are likely some optimizations to be done there for it to
not re-calculate the tree when the mouse hasn't moved.

I couldn't figure out how to change the background color to white in
Helm so it's red on black.

Ciao,

Kaspar