Small, fast, accessible, mobile friendly text editor for Moodle
Put this entire directory at:
PATHTOMOODLE/lib/editors/atto
Visit your site notifications page to install the new plugins.
Enable the new editor on the page:
Site administration / ► Plugins / ► Text editors / ► Manage editors
To make it the default, change the order so this editor is the first in the list.
In Moodle 2.6 users can also choose this editor from their profile preferences.