Expose getOpenFileName to scripts

Change-Id: Ic3ddbb1f3ddfd72e93f9408dd9a5d5b6fa6cbf71
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>