Use the default back end theme when running in safe mode (see #6505)
Do not replace a widget's name with an empty label (see #6501)
Prevent the ACE editor from overlapping the modal window (see #6497)
Fix the ACE editor resizing
Fix more JSDoc comments
Re-compress all assets with the new YUI compressor

This will add a whitespace character before every `!important` statement.
Remove a redundant field definition from the `tl_settings` DCA
Update the ACE editor to version 1.1.2
Use the ACE editor where applicable
Use an auto-resizing textarea to enter CSS selectors
Show the security relevant palettes of `tl_settings` by default
Fix the Stylect conversion if there are no options
Hide records with only one version from the "changed elements" overview

Opening the diff view would only show the "there are no versions" message.
Handle UUIDs in `Model::getRelated()` (see #6525)
Correctly handle URLs if page aliases are disabled (see #6502)
Correctly outline the enhanced select menus upon focus (see #6510)
Only enable the safe mode if there are third-party modules (see #6514)
Add `.ogv` to the default list of uploadable/downloadable files (see #6516)
Remove a redundant whitespace character from the `Model` class
Do not override the "href" property in `addImageToTemplate()` (see #6468)