Fogger JS API should expose window information to DOM

[Owais Lone]

Currently there is no way for a user script to know if the window is focused or not. Fogger JS API should expose

    Fogger.getWindowActive()

and should also emit a JS event when focus on Window changes. This essentially means propagating the Gdk.Window.State changes to DOM.

[Owais Lone (loneowais)]

Fixed.

Fogger emits 'foggerWindowStateChange' signal when window state changes.

'fogger.desktopWindow.active' reflects if a window is active or not