Avocado seed stand

OpenSCAD customizer version of the excellent Avocado stand by [t_colon](http://www.thingiverse.com/t_colon). There are two versions derived from t_colon's [single](http://www.thingiverse.com/thing:1146533) and [quad](http://www.thingiverse.com/thing:1174072) variants.

The customizer offers some range of sizes and uses less material in the legs.
See how to use them on teh original page. Link to excellent article.
(Parameter limitations as code could do with more work to make legal variants w