Eslint goes to es6 (#289)

* Reconfiguration of eslint to work in ES6 environment and changes on some rules to get closer to WP standards while retaining the specificity of JavaScript

* fixes #285 replace deprecated chrome.extension.getURL with chrome.runtime.getURL

* add missing global functions to eslint

* correction of #289 (comment)

* revert jquery.bind-first.js to previous version and add eslintignore file to ignore dompurify, jquery.bind-first and keymaster

* move spaces #289 (comment)

* changing eslint rule for object alignment so that they are more readables

Author: webaxones

.eslintignore

@@ -0,0 +1,4 @@
+# Dependencies
+js/dompurify.js
+js/jquery.bind-first.js
+js/keymaster.js