Auxetic 3D-mezostructures

Autexic material lattice (with in theory a negative poisson ratio) based on this drawing:
http://silver.neep.wisc.edu/~lakes/PoiNYTimesCell.jpg

and a recent academic article (published 5 July 2016):
"Negative Poisson's Ratio in Modern Functional Materials"
by Huang et al DOI: 10.1002/adma.201601363 , figure 20b.

They are parametric, so you can adjust the angles and inclinations.

TODO:
* Test print (without support?)
* implement Triclinc lattice. => done.
* update shift parameter

Constructive Comments or suggestions welcome!