Refactor: Reorganize client directories

Remove the 'js' folder, as I've spent many
times confused by its presence, since almost
everything is JavaScript.

 * js -> main
 * js/lib -> lib
 * js/services -> services
 * js/partials -> ui/views
 * js/controllers -> ui/controllers

Someday the css and img folders might move
into ui, but that change is more prone to
error, so it will have to wait.