switch to version 3.1.1

Author: Martin Grenfell

doc/NERD_tree.txt

@@ -997,7 +997,7 @@ The latest dev versions are on github
 ==============================================================================
 6. Changelog                                               *NERDTreeChangelog*
 
-3.x.x
+3.1.1
     - fix a bug where a non-listed no-name buffer was getting created every
       time the tree windows was created, thanks to Derek Wyatt and owen1
     - make <CR> behave the same as the 'o' mapping

plugin/NERD_tree.vim

@@ -2,15 +2,15 @@
 " File:        NERD_tree.vim
 " Description: vim global plugin that provides a nice tree explorer
 " Maintainer:  Martin Grenfell <martin_grenfell at msn dot com>
-" Last Change: 27 Jan, 2009
+" Last Change: 7 Jun, 2009
 " License:     This program is free software. It comes without any warranty,
 "              to the extent permitted by applicable law. You can redistribute
 "              it and/or modify it under the terms of the Do What The Fuck You
 "              Want To Public License, Version 2, as published by Sam Hocevar.
 "              See http://sam.zoy.org/wtfpl/COPYING for more details.
 "
 " ============================================================================
-let s:NERD_tree_version = '3.1.0'
+let s:NERD_tree_version = '3.1.1'
 
 " SECTION: Script init stuff {{{1
 "============================================================