Table saw zero clearance thoat plate

* zero clearance table saw insert
* throat plate
* (modelled in 2 parts for smaller printers)
*
* this is my first project in OpenSCAD!
* please provide support or improvements by commenting
*
* TO DO:
* - make the number of interlocking triangles and blocks based on plate width
* - make corner radius max dependent on half plate width
* - limit support variables on all plate dimensions
* - how to export both halfs separately? (workaround used: place percent sign for all elements than close without saving or replace all by nothing)
* - tests with all variable ranges. Currently perfect settings for Robland combination machine but maybe some drawing errors with different machine dimensions.
* - the interlocking triangles and blocks are for alignment only. The two parts need a contineous support glued underneath finally.
*
* Author:
* - Erik Schulte, The Netherlands 2020 -