Use eslint and stylelint, fix all errors (#282)

* Use eslint and stylelint, fix all errors

* Remove jshint, jsbeautify
* Use Object.keys directly since that is available in all major browsers
* Fixes for eslint, stylelint errors
* stylelint is not included in grunt test yet because jquery.uls.mobile.css
  has so many !important and need to figure out whether they are really needed

.eslintrc.json

@@ -0,0 +1,14 @@
+{
+	"extends": "wikimedia",
+	"env": {
+		"browser": true,
+		"jquery": true,
+		"qunit": true
+	},
+	"globals": {
+		"require": false
+	},
+	"rules": {
+		"dot-notation": [ "error", { "allowKeywords": true } ]
+	}
+}