threadlib emancipation

+++++++++++++++++++++++

threadlib is now its own project => remove Waterrocket Fins from this
repo.

test.scad

@@ -0,0 +1,23 @@
+/*
+Test and demonstrate thread library
+
+:Author: Adrian Schlatter
+:Date: 2019-04-07
+:License: 3-Clause BSD. See LICENSE.
+*/
+
+use <threadlib.scad>
+
+type = "G1";
+turns = 5;
+Douter = thread_specs(str(type, "-int"))[2] * 1.2;
+
+intersection() {
+    color("Green")
+        translate([-100, 0, -100])
+            cube(200, 200, 200);
+    union() {
+        bolt(type, turns);
+        nut(type, turns, Douter);
+    };
+};