Pathwayz sidebar

Cleans up code from PR #247 for clearer understanding of what is happening:

More specifically it follows OOCSS conventions for cleaner files && a better understanding of what is going on for anyone that wants to debug later

Interesting fact: 
buttons files went from `160 lines to 98 o.O`
pathway-editor went from `45 lines to 26 -.o`
and html is much `cleaner` now

I was not able to refactor the js much but i did move the event handlers in editor.js on top of initialize as per backbone conventions. 

Once this PR is merged it adds the add, delete, undo, etc sidebar to the pathway pledge page as per #269