initial setup for editor page to generate graph through textarea input

Hi! I have added a initial setup for a html editor page so a user can create and edit and generate a graph from a web page. I just discovered the repo in a blog post but was missing this page to just be able to create a graph with the syntax at hand. I have ...

* Added a editor folder with the index.html page and the files needed to load the editor
* Added a basic CSS setup, configured with LESS 
* Updated gulp, bower and package.json to handle less preprocessor and buld.js for the editor page.

This is the basics, needs some styling hands and an some clean up to the left side doc. column. Glad to help if theres any questions. With some update to this you could branch it into a http://knsv.github.io/mermaid/  gh-page.