Add new objects.

manufacture/material_holder.3D.scad

@@ -0,0 +1,4 @@
+include <../assets/material_holder.scad>
+
+$fn = 100;
+material_holder_object();

manufacture/strong_angler.3D.scad

@@ -0,0 +1,4 @@
+include <../assets/strong_angler.scad>
+
+$fn = 100;
+strong_angler_object();