Replace CodeMirror with ACE (see #5332)
Remove the MooTools compat layers (will break ACE)
Move the "edit source" button of the template editor to the right
Do not show the upload button in "edit multiple" mode
Add `border-box` to the ACE container
Fix various issues and make the key/value wizard sortable
Adjust the media player help texts (see #5507)
Add the "modifyFrontendPage" hook (see #4291)
Allow to shorten the calendar day names via CSS (see #5462)
Add more options to the event list module (see #5481)