* Rename `WindowEvent::Resized` to `SurfaceResized`
* Rename `InnerSizeWriter` to `SurfaceSizeWriter`
* Replace `inner_size` with `surface_size`
* Rename `resize_increments` to `surface_resize_increments`
This should allow us to make future split of backends much easier.
The `Box<dyn Window>` is a _temporary_ solution, which will be
removed with the future updates when we decide on how the Window
should be stored.
Fixes issue on Wayland due to drop order, since TLS is being dropped
after the event loop, while it shouldn't. In particular it fixes the
crash in the window_run_return example.
