18650 Battery Box

This is the first incarnation of the 18650 battery box. I was inspired by the Rocket Box to create a solderless 18650 battery holder. More update (instruction, tweaks, etc) to come. Pull requests accepted @ github.com/pmorton/battery_box.

2018-01-16 - Updated the battery box to print faster. Analyzed the gcode and eliminated a number of time-consuming moves.