Brought the AuthManager and User classes more in line with Laravel's Auth library.

UX/UI Improvements

• Implemented easy impersonation of backend users through the backend - feature controlled by the new backend.impersonate_users permission
• Open rowlink rows in a new tab when the Command or Ctrl key is held down (previously only did it for the Ctrl key)
• Added disabled style for switch field types

API Changes

• Changed the FileUpload FormWidget to process uploads with a onUpload AJAX handler instead of the checkUploadPostback method
• Changed the default value of cache.disableRequestCache to be null which now disables the in memory request cache during CLI requests and enables it during HTTP requests. Other values are explicit true or false.
• Brought the AuthManager and User classes more in line with Laravel's Auth library; full support is still a far ways off though.
• Removed the mediafinder buttons from the RichEditor and MarkdownEditor FormWidgets when the user does not have permission to use the media library.

Bug Fixes

• Fixed issue with retaining transparency when making thumbnails for some image files
• Fixed issue that could cause potential data loss with complicated implementations of the Repeater formwidget.
• Fixed issue where the DatePicker was ignoring the value of ignoreTimezone when in mode date

Translation Improvements

• Improved Dutch translation