Fix lint task so it prints error messages

Author: simonsmith

package.json

@@ -27,7 +27,7 @@
   "scripts": {
     "build": "npm run setup && npm run preprocess",
     "build-test": "npm run setup && npm run preprocess-test",
-    "lint": "suitcss index.css >/dev/null",
+    "lint": "suitcss index.css build/lint.css",
     "preprocess": "suitcss index.css build/build.css",
     "preprocess-test": "suitcss -i test test/test.css build/test.css",
     "setup": "npm install",