Use Windows taskbar extension features

[AndreSomers]

When running Charm on Windows, it would be nice to use the taskbar extension features to offer some quick access to features:

• A start/stop button and quick task switch (2/3 most recent tasks?) using the Thumbnail Toolbar. Should also indicate the currently running task clearly if a task is currently active.
• A bigger list of recent tasks to start using the Jump list.

This would make it easier to use Charm without having to actually bring the window to the front.

[frankosterfeld]

Note to team: See https://msdn.microsoft.com/en-us/library/windows/desktop/dd378460(v=vs.85).aspx and http://doc.qt.io/qt-5/qtwinextras-overview.html

[AndreSomers]

Well, Qt has direct support for it on Windows: http://doc.qt.io/qt-5/qtwinextras-overview.html