Wayland: implement touch events (#342)

* wayland: move pointer to its own file

* wayland: touch events support

* update changelog

src/platform/linux/wayland/mod.rs

@@ -11,6 +11,8 @@ use wayland_client::protocol::wl_surface;
 use wayland_client::Proxy;
 
 mod event_loop;
+mod pointer;
+mod touch;
 mod keyboard;
 mod window;