Replaced update info and element toggle spinners with spin,js
Refactors the ElementEditorSelector javascript module.

- Renamed into ElementEditors
- Uses spin.js for toggleFold spinner.
Converts Alchemy.base.js into coffeescript and uses spin.js for "please wait overlay" spinner.
Removes the spinner gif from flash uploader partial.
Replaces the TinyMCE initialize spinner with spin.js and removes ajax_loder.gif

Bye bye old fella.