gui_toolkit 0.109.0

Added

• platform.hide_window: a shown window off the screen and back with show_window in a few milliseconds, its interface kept (a program in the notification area): Wayland (the toplevel role made again, its first configure waited for), X11 (withdrawn), Windows (SW_HIDE). Window.shown_again counts the shows after a hide; host_frame then makes a new swap chain (render.surface_remake), which Vulkan's FIFO on Wayland would otherwise wait on for good.