Corrected some English phrases
Changed some English phrases in setting.inc.php (part 1)
Merge remote-tracking branch 'upstream/develop' into English_phrases
Changed some English phrases (up to tv_widget.inc.php), additionally changed all occurrences of "e-mail" to "email"
Changed some English phrases (finished pass 1 - there's still a lot of inconsistencies!)
Media browser tree icons

Change from .png to FontAwesome icons
Outsourcing window styles to _windows.scss, first restyling attempts
Finished basic window restyling
Enhance quick update window with allfields from document/settings tabs, further window style improvements
Rebase on #11617 and cleanup of _windows.scss
Prevent saving an empty pagetitle with the quick update window
Make Quick Update content field a bit bigger (min-height 200px) and grow with the content
Make datetime.js globally available to prevent error on non-resource fields when using quick update resource from the tree
Add xtype fileuploadfield via additonal util fileupload, replace the file inputs in import windows and style them
Make fileuploadfield button text use lexicon
Fix fieldsets in windows (margin-bottom somehow not applied)
Refactor and re-style the .x-tool * icons/buttons (window/panel collapse) and use fontawesome icons
Fix windows maximized view
Extensive forms and window work including topbar fixes
Adjust ComboBox dropdown list selected bg to be the same as hovered nodes in the tree