OpenSCAD ASCII to decimal number function

This library includes a function to convert Strings into floating point numbers. It's useful if you are generating OpenSCAD files using a customizer program and want to put user HTTP form data directly into the file.

For example, using atof("%size%") in the template file could get replaced with atof("60.5") which returns 60.5 as a number. The atof("%size%") placeholder still allows the OpenSCAD document to pass compilation which helps with debugging.