Edit mode

[TorsteinHonsi]

Edit source code directly in Utils. Replaced the View source pane with Edit, that allows us to edit, run and save. Also allows Save As..., which is a convenient way of copying demos.

[pawelfus]

Nice, I love it!

A few things though:

• - Update readme.md about the new way to start the server
• - enter edit mode, exit edit mode, click Bisect button: the bisect frame lands somewhere below everything

Nice to have:

• - when quitting Edit mode, it would be nice to NOT reload the list of demos, it takes on my machine extra ~10s when I just wait and watch loading the sidemenu, then scrolling it way to the bottom:
  

[pawelfus]

(the above should be request changes, not a comment - just a misclick)

[TorsteinHonsi]

Done, except this one:

Update readme.md about the new way to start the server

I didn't think of the case when the server is started with sudo node server. I tried to call Rollup from server.js, but it currently fails with a syntax error. Will try to make it work.