Several improvements to ScreenShotViewer:
- Only allow one dialog to be open at a time, to protect against accidental multiple clicks
- Set the busy cursor while waiting for the dialog to show
- Give the screenshot in the window a drop shadow and a bit of a buffer zone, to help prevent confusion on whether or not the screenshot is an actual window.
- Rip out a bunch of unnecessary code; We already fetched the screenshot as a KTemporaryFile in the ApplicationDetailsWidget, so a full-blown KIO grab to another temp file isn't really necessary