Do not throw an Exception if a model does not (yet) reference a relation (see #6161)
Use `display:table` to clear floats in the back end (see #6093)
Use absolute URLs in the front end preview redirect (see #4332)
Hide the `lastLogin` field in the details view (see #5949)
Make the CSS ID available in the custom navigation module (see #6129)
Correctly link to news and calendar feeds via insert tag (see #6164)
Do not require a `DataContainer` object in `tl_content::showJsLibraryHint()` (see #6157)
Only show the "build the internal cache" message to admins (see #6156)