Hex Shank Bit Holder - Parametric

I've modified the scad file from "Fitzterra" to add more customization and powerfull features, that adds:

* More shapes (Triangle and square)
* Custom size and shapes per row and cols
* Label per hole
* Allow allen key slots
* Global tolerance for holes
* More aesthetics

All holders i generate (I like them bulky), will post them here, so check the variants i put:

* 8x2 Hex Shank with Slot for allen keys.
* 6 Hex Shank + 6 Round bits with Slot for allen keys.
* WoodBits: 8 Hex Shank + 8 Round
* Spades: 14 Hex Shank Irregular slots as mine come that way

# Changelog

**17/04/2019:**
* Added magnetic base
* Added left and right label
* Fixed label depth was 0.1mm off

**12/04/2019:**
* Added more shapes (pentagon, heptagon, octagon)
* Added 'holeTolerance' to Allen Key Diameter
* Added 'hexHoleDiameterIsLongDiagonal' variable: When using hex holes, specify if the diameter given is from long diagonal (1) or short diagonal (0). Tip: Short diagonals are easier to