Fix the Travis build

The tests, as I so clearly wrote a comment to indicate, can only be run after the script to generate the testcases has been run...

.travis.yml

@@ -8,6 +8,7 @@ rust:
   - stable
 script:
     - cargo build --verbose
+    - sudo ./generate-testcases.sh
     - cargo test --verbose
     - cargo run
     - cargo run -- --long