Added head.min.js and Modified the index page.

Since the scripts were loading in an blocking fashion, I added head.min.js in order to load the scripts asynchronously and also edited the index.html page a bit so as to call the head.js() function in order to load all the scripts simultaneous. I thought this could add a bit to the performance if the editor get along with some more functionality.Hope you like the small addition. Makes it load faster :+1: