Adds a virtual camera button to the main user interface.  If virtual
camera is not installed, it will not add the button.  On Windows, it
detects whether the virtual camera filters are properly registered, and
will only add the button if the virtual camera filter is confirmed
registered.

Also adds a virtual camera option to the auto-configuration wizard,
which will just simply set the user's resolution/scale to 1920x1080 at
30 FPS.