Implement touch events via winit

[marysaka]

Tested on iOS

[wtholliday]

Looks good! How do I run with winit on iOS?

[marysaka]

Looks good! How do I run with winit on iOS?

I'm working on tools to build iOS app entirely in Rust without depending on xcode

This is currently unreleased but I'm using the example from the readme directly and it does work

use rui::*;

fn main() {
    rui(state(
        || 1,
        |count, cx| {
            vstack((
                cx[count].padding(Auto),
                button("increment", move |cx| {
                    cx[count] += 1;
                })
                .padding(Auto),
            ))
        },
    ));
}

Something to note however is that as it, position are broken on my iPhone 12.
winit will return the outer_size of the window on resize instead of the inner_size (rust-windowing/winit#2347)

My initial workaround is also not enough if you don't target iOS 7.0 as it seems wgpu entirely ignore the size you give to it and use the whole screen (ignoring safe areas).

I ended up forcing rui to use the outer_size everywhere instead and it does works that way. (see marysaka@6ee75ef)

[marysaka]

I fixed build issues with tao.

Also rebased on top of the main branch.

[wtholliday]

Thanks!!