Simple Hexagonal Packing Within A Circle

This is an extremely simplified version of [Circle Packing](https://en.wikipedia.org/wiki/Circle_packing) algorithm for filling the area of a circle with other circles. It by no means is anywhere near as complicated or accurate as real-world circle packing algorithms and I'm sure could be improved upon as my OpenScad skills are fairly new and i'm sure the math could be cleaned/simplified. It creates a hexagonal grid of points at which we draw a circle on. Based completely on the work @ [Red Blog Games](http://www.redblobgames.com/grids/hexagons/) and ported to OpenSCAD, specifically the [Movement Range](http://www.redblobgames.com/grids/hexagons/#range) section.