Fibonacci Sphere: A Smoother Sphere for OpenSCAD

##What it is:
A [fibonacci sphere](http://onlinelibrary.wiley.com/doi/10.1256/qj.05.227/pdf) is an approximation for a sphere that is formed from an arbitrary number of roughly equidistant vertices. Pass it any positive number and you'll get a mesh back containing that exact number of vertices for each hemisphere. All vertices in the sphere will be roughly equidistant.

##What this means to you:
* You get a sphere model that looks better while using fewer vertices.
* You have precise control over the number of vertices used.
* In theory, this also allows `minkowski()` to deliver smoother renders in the same amount of time.

##How it works:
Vertices start out at the meridian and are spaced at regular intervals along the z axis. With that, each vertex is rotated away from its predecessor by a certain angle. That angle is 360 degrees divided by the [golden ratio](http://en.wikipedia.org/wiki/Golden_ratio).
For those who want a gentle (and fascinating) int