Use the new HTML5 form fields in the front end (see #4138)
Support `url()` with single quotes in the Combiner (see #5253)
Add the `File::resizeTo()` method (see #3883)
Enhance the `File::__get()` method with more image parameters (see #3760)
Use the module names as back end wildcards (see #5314)
Use the translated labels for fieldset wrappers (see #5314)
Add an option to purge the system log to the maintenance module (see #4701)
Insert tags now support flags (see #4717)
Skip links to news/events if the target page has not been published (see #5520)
Update all language files
Set the release date and bump the version numbers
Merge branch 'hotfix/3.0.6'
Merge branch 'hotfix/3.0.6' into develop

Conflicts:
	system/config/constants.php
	system/docs/CHANGELOG.md
Add new methods to models and model collections
Disable certain `tl_page` operations in the modal dialog
Trigger an `E_USER_WARNING` for unknown insert tag flags (see #4717)
Always show 7 links in the versions pagination in the back end
Only show unknown insert tags and insert tag flags in debug mode
Add class "ce_accordion" to the accordion elements
Replace `$exec()` with `Browser.exec()`