Vim 8.1 release

Update version number and information.  Fix a couple of tests.
diff --git a/runtime/doc/gui_w32.txt b/runtime/doc/gui_w32.txt
index d8052fe..9d676ea 100644
--- a/runtime/doc/gui_w32.txt
+++ b/runtime/doc/gui_w32.txt
@@ -1,4 +1,4 @@
-*gui_w32.txt*   For Vim version 8.0.  Last change: 2017 Oct 27
+*gui_w32.txt*   For Vim version 8.1.  Last change: 2017 Oct 27
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar