Add recent pattern for ESLinting in repo

Use of all: '.' in Gruntfile.js for eslint config and
eslintIgnore in package.json to ignore linting the "vendor/"
directory.

Change-Id: Ic8489351b8de6b7e31a95a55420db1f772f8d535

Gruntfile.js

@@ -9,11 +9,7 @@ module.exports = function ( grunt ) {
 			all: 'i18n/'
 		},
 		eslint: {
-			all: [
-				'**/*.js',
-				'!node_modules/**',
-				'!vendor/**'
-			]
+			all: '.'
 		},
 		jsonlint: {
 			all: [

package.json

@@ -9,5 +9,8 @@
     "grunt-banana-checker": "0.6.0",
     "grunt-eslint": "20.0.0",
     "grunt-jsonlint": "1.1.0"
-  }
+  },
+  "eslintIgnore": [
+    "vendor/**"
+  ]
 }