Introduce a WindowProxy for accessing a subset of functionality

from other threads. This currently provides a way for other threads
to wakeup a blocked event loop on X11. Other platforms have stub
functions that need to be implemented. This is similar to
the functionality of glfwPostEmptyEvent.

src/android/mod.rs

@@ -207,6 +207,10 @@ impl Window {
     pub fn set_inner_size(&self, _x: uint, _y: uint) {
     }
 
+    pub fn create_window_proxy(&self) -> WindowProxy {
+        WindowProxy
+    }
+
     pub fn poll_events(&self) -> Vec<Event> {
         use std::time::Duration;
         use std::io::timer;
@@ -271,6 +275,16 @@ impl Window {
     }
 }
 
+#[cfg(feature = "window")]
+#[deriving(Clone)]
+pub struct WindowProxy;
+
+impl WindowProxy {
+    pub fn wakeup_event_loop(&self) {
+        // TODO
+    }
+}
+
 #[unsafe_destructor]
 impl Drop for Window {
     fn drop(&mut self) {