ace-window.el (aw-switch-to-window): Push early

* ace-window.el (aw-switch-to-window): Push current window to ring
  before switching frames. It's OK to push without checking, the check
  is performed in `aw--push-window'.

Fixes #61

ace-window.el

@@ -423,13 +423,12 @@ Windows are numbered top down, left to right."
 (defun aw-switch-to-window (window)
   "Switch to the window WINDOW."
   (let ((frame (window-frame window)))
+    (aw--push-window (selected-window))
     (when (and (frame-live-p frame)
                (not (eq frame (selected-frame))))
       (select-frame-set-input-focus frame))
     (if (window-live-p window)
-        (progn
-          (aw--push-window (selected-window))
-          (select-window window))
+        (select-window window)
       (error "Got a dead window %S" window))))
 
 (defun aw-flip-window ()