Support for undocked video during AppShare

Prior to this update, the video was always docked when the session host started AppShare.

This update now supports undocked video when the session host starts AppShare only if multiple screens are present. A new Undock icon is added to the video panel and is displayed in the undocked frame. Additionally, the undocked video frame is shown in a screen other than the one the Apphosting toolbar is displayed in.

The following figure shows undocked video during AppShare with multiple screens.