Use this to easily include a build plate into your Customizer scripts so it's easy to see how big your customizable thing is.
To include a build plate selector in your Customizer script, use utils/build_plate.scad and include the following code:
//for display only, doesn't contribute to final object
build_plate_selector = 0; //[0:Replicator 2,1: Replicator,2:Thingomatic,3:Manual]
//when Build Plate Selector is set to "manual" this controls the build plate x dimension
build_plate_manual_x = 100; //[100:400]
//when Build Plate Selector is set to "manual" this controls the build plate y dimension
build_plate_manual_y = 100; //[100:400]