remove ace-window

.gitmodules

@@ -157,9 +157,6 @@
 [submodule "site-lisp/saveplace-pdf-view"]
 	path = site-lisp/saveplace-pdf-view
 	url = https://github.com/nicolaisingh/saveplace-pdf-view.git
-[submodule "site-lisp/ace-window"]
-	path = site-lisp/ace-window
-	url = https://github.com/abo-abo/ace-window.git
 [submodule "site-lisp/markdown-mode"]
 	path = site-lisp/markdown-mode
 	url = https://github.com/jrblevin/markdown-mode.git