Build the direct-composition demo on Appveyor CI

SimonSapin · SimonSapin · commit 2c52c90f1ec3 · 2018-03-09T17:58:40.000+01:00
diff --git a/appveyor.yml b/appveyor.yml
@@ -18,3 +18,5 @@ test_script:
   - cargo test --verbose
   - cd ../wrench
   - cargo test --verbose
+  - cd ../direct-composition
+  - cargo build --verbose
