Fix clippy warnings and add to CI

.travis.yml

@@ -52,8 +52,8 @@ matrix:
     - cargo fmt --version
     - cargo fmt --all -- --check
     - rustup component add clippy-preview
-#    - cargo clippy --version
+    - cargo clippy --version
-#    - cargo clippy
+    - cargo clippy
 
   - name: Book
     rust: stable

src/command/utils.rs

@@ -30,7 +30,7 @@ fn find_manifest_from_cwd() -> Result<PathBuf, failure::Error> {
                 return Ok(PathBuf::from("."));
             }
         } else {
-            return Ok(parent_path.to_owned());
+            return Ok(parent_path);
         }
     }
 }

src/manifest/mod.rs

@@ -590,7 +590,7 @@ impl CrateData {
         files.push(js_file.clone());
         if include_commonjs_shim {
             let js_bg_file = format!("{}_bg.js", name_prefix);
-            files.push(js_bg_file.to_string());
+            files.push(js_bg_file);
         }
 
         let pkg = &self.data.packages[self.current_idx];

src/npm.rs

@@ -28,7 +28,7 @@ pub fn npm_publish(
         None => cmd.current_dir(path).arg("publish"),
     };
     if let Some(tag) = tag {
-        cmd.arg("--tag").arg(&tag.to_string());
+        cmd.arg("--tag").arg(tag);
     };
 
     child::run(cmd, "npm publish").context("Publishing to npm failed")?;