Fix poll_events returning None when it shouldn't

src/x11/window/mod.rs

@@ -119,6 +119,7 @@ impl<'a> Iterator for PollEventsIterator<'a> {
             return Some(ev);
         }
 
+        loop {
             let mut xev = unsafe { mem::uninitialized() };
             let res = unsafe { ffi::XCheckMaskEvent(self.window.x.display, Int::max_value(), &mut xev) };
     
@@ -238,8 +239,7 @@ impl<'a> Iterator for PollEventsIterator<'a> {
     
                 _ => ()
             };
-
-        return None;
+        }
     }
 }