Mirror monitor list methods on Window (#567)

* macOS: Monitor list methods on Window

* X11+Wayland: Monitor list methods on Window

* Windows: Monitor list methods on Window

* iOS: Monitor list methods on Window

* Android: Monitor list methods on Window

* Emscripten: Monitor list methods on Window

* Fixed Wayland implementation

examples/monitor_list.rs

@@ -0,0 +1,7 @@
+extern crate winit;
+
+fn main() {
+    let event_loop = winit::EventsLoop::new();
+    let window = winit::WindowBuilder::new().build(&event_loop).unwrap();
+    println!("{:#?}\nPrimary: {:#?}", window.get_available_monitors(), window.get_primary_monitor());
+}