change shown list with ajax

[mftaff]

It would be nice UX to ajax the list switching. So when a user toggles between lists, there is no page reload

(on the show/home page there is a bar with all users lists displayed. that should be ajax)

Notes:

• in the list controller there is already commented out lines supporting an ajax call.
• add remote true to the form
• new files: create.js.erb, and destroy.js.erb in lists/