feat(CI): Check for code-smells

Author: epage

.travis.yml

@@ -8,12 +8,22 @@ rust:
 
 matrix:
   include:
-  - rust: 1.24.0  # `stable`: Locking down for consistent behavior
-    env: RUSTFMT
+  - env: RUSTFMT
+    rust: 1.24.0  # `stable`: Locking down for consistent behavior
     install:
     - rustup component add rustfmt-preview
     script:
     - cargo fmt -- --write-mode=diff
+  - env: RUSTFLAGS="-D warnings"
+    rust: 1.24.0  # `stable`: Locking down for consistent behavior
+    script:
+    - cargo check --tests
+  - env: CLIPPY_VERSION=0.0.179
+    rust: nightly-2018-01-12
+    install:
+    - travis_wait cargo install clippy --version $CLIPPY_VERSION || echo "clippy already installed"
+    script:
+    - cargo clippy -- -D clippy
 
 install:
 - rustc -Vv