Update devDepedencies.

/CC @cvrebert: let's see if tests pass; every dep should work with Grunt 1.x now. For ESLint, I haven't checked if we can/should change any rules.

.travis.yml

@@ -19,7 +19,6 @@ before_install:
 install:
   - bundle install --deployment --jobs=3
   - cp grunt/npm-shrinkwrap.json ./
-  - npm install -g grunt-cli
   - npm install
 cache:
   directories:

package.json

@@ -43,8 +43,8 @@
   "devDependencies": {
     "autoprefixer": "^6.0.3",
     "babel-eslint": "^6.0.4",
-    "eslint": "^2.11.1",
-    "grunt": "^0.4.5",
+    "eslint": "^3.0.0",
+    "grunt": "^1.0.1",
     "grunt-babel": "^5.0.3",
     "grunt-build-control": "^0.7.0",
     "grunt-contrib-clean": "^1.0.0",
@@ -63,7 +63,7 @@
     "grunt-sass": "^1.0.0",
     "grunt-saucelabs": "^8.6.1",
     "grunt-scss-lint": "^0.3.8",
-    "grunt-stamp": "^0.2.0",
+    "grunt-stamp": "^0.3.0",
     "is-travis": "^1.0.0",
     "jscs": "^3.0.4",
     "load-grunt-tasks": "^3.4.0",