Check rustfmt on Travis

Author: Amanieu

.travis.yml

@@ -32,7 +32,12 @@ branches:
     - trying.tmp
     - staging.tmp
 
+before_script:
+  - if [ "$TRAVIS_RUST_VERSION" == "stable" ]; then rustup component add rustfmt; fi
+
 script:
+  - if [ "$TRAVIS_RUST_VERSION" == "stable" ]; then cargo fmt -- --check; fi
+
   - cargo build --verbose --features "$FEATURES"
   - cargo test --verbose --features "$FEATURES"
   - if [ "$TRAVIS_RUST_VERSION" == "nightly" ]; then cargo bench --verbose --features "$FEATURES"; fi