Check prettier status when linting

We want to ensure that all code conforms to prettier.

Ideally contributors will have the prettier plugin for their editor to
autoformat-on-save and they won't have to do anything manually.

Also, remove eslint-prettier plugin since it's not being used anymore.

.eslintrc

@@ -112,7 +112,6 @@
     "no-plusplus": 0
   },
   "plugins": [
-    "prettier",
     "react"
   ],
   "extends": ["plugin:react/recommended"]

package.json

@@ -40,7 +40,6 @@
     "babel-preset-stage-0": "^6.3.13",
     "css-loader": "^0.23.1",
     "eslint": "^3.14.1",
-    "eslint-plugin-prettier": "^2.3.1",
     "eslint-plugin-react": "^7.4.0",
     "font-awesome-webpack": "0.0.4",
     "jasmine-core": "^2.4.1",
@@ -68,7 +67,7 @@
     "start": "node server.js",
     "build":
       "BABEL_ENV=production webpack --config webpack.config.production.js && node pre-render.js",
-    "lint": "eslint .",
+    "lint": "eslint . && prettier --list-different '**/*.{js,jsx,ts,css,less,scss,json}'",
     "test": "karma start --single-run --browsers PhantomJS",
     "pretty": "prettier --write '**/*.{js,jsx,ts,css,less,scss,json}'"
   }