Vim 8.1 release

Update version number and information.  Fix a couple of tests.
diff --git a/runtime/doc/debug.txt b/runtime/doc/debug.txt
index 4547eab..6d2cea5 100644
--- a/runtime/doc/debug.txt
+++ b/runtime/doc/debug.txt
@@ -1,4 +1,4 @@
-*debug.txt*     For Vim version 8.0.  Last change: 2017 Jul 15
+*debug.txt*     For Vim version 8.1.  Last change: 2017 Jul 15
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar