Fix my STL export issue (I needed to truncate old files)

README.md

@@ -2,8 +2,6 @@
 
 ## Highest priority:
 
-- Fix my fucked STL export at max_iters=4.  Blender & Wings refuse to
-  load.
 - Fix `OpenMesh.connect()`.
 - Continue converting `curve_horn_*`.
 
@@ -19,3 +17,6 @@
 ## If I'm bored:
 
 - Fix links in tri_mesh docs that use relative paths & do a PR?
+- Look in https://www.nalgebra.org/quick_reference/# for "pour
+  obtain".  Can I fix this somehow?  Looks like a French-ism that made
+  its way in.

src/main.rs

@@ -49,7 +49,7 @@ impl OpenMesh {
     }
 
     fn write_stl_file(&self, fname: &str) -> io::Result<()> {
-        let mut file = OpenOptions::new().write(true).create(true).open(fname)?;
+        let mut file = OpenOptions::new().write(true).create(true).truncate(true).open(fname)?;
         self.write_stl(&mut file)
     }
     
@@ -602,7 +602,7 @@ fn main() {
 
     let r = Rule::Recurse(cube_thing_rule);
 
-    let max_iters = 5;
+    let max_iters = 4;
     println!("Running rules...");
     let (cubemesh, nodes) = rule_to_mesh(&r, max_iters);
     println!("Merged {} nodes", nodes);