OK sthen@
Most important changes since beta 11:
greatly improved tab bar:
allow to detach tabs by dragging them away;
allow to drop URLs and tabs from other windows;
added option to show embedded tab thumbnails;
improved handling of visibility of close button;
tabs demanding attention are drawn using bold font;
improved RTL support;
decreased default tab padding;
tab text is no longer centered horizontally;
fixed status tip messages while rearranging tabs;
improved KDE5 and Unity integration:
added support for progress information;
added support for desktop actions;
several MacOS X specific fixes and improvements:
improved rendering of platform style;
added dock icon menu;
added support for listing applications associated with given MIME type;
added support for Windows jump list;
added fullscreen support for QtWebKit backend;
open file path is saved;
improved RTL support in address and search fields;
many other fixes and improvements.
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