Vim 8.1 release

Update version number and information.  Fix a couple of tests.
diff --git a/runtime/doc/autocmd.txt b/runtime/doc/autocmd.txt
index 70dd43a..703590a 100644
--- a/runtime/doc/autocmd.txt
+++ b/runtime/doc/autocmd.txt
@@ -1,4 +1,4 @@
-*autocmd.txt*   For Vim version 8.0.  Last change: 2018 May 03
+*autocmd.txt*   For Vim version 8.1.  Last change: 2018 May 03
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar