Make it possible to set the command to cd

Signed-off-by: Jo De Boeck <deboeck.jo@gmail.com>

doc/NERDTree.txt

@@ -630,6 +630,9 @@ NERD tree. These options should be set in your vimrc.
                                 at the beginning of the hidden file names
                                 into account when sorting nodes.
 
+|'NERDTreeChDirCWD'|            Tells the NERD tree which command to use to
+                                change dir.
+
 |'NERDTreeChDirMode'|           Tells the NERD tree if/when it should change
                                 vim's current working directory.
 
@@ -776,6 +779,17 @@ above nodes would then be sorted like this: >
     z100.txt
     z110.txt
 <
+
+------------------------------------------------------------------------------
+                                                         *'NERDTreeChDirCMD'*
+Values: cd, lcd or tcd.
+Default: cd.
+
+Use this option to change the way NERDTree changes directory.
+Use cd to change vim's global directoy.
+Use lcd to change the directory for the curent window.
+Use tcd (neovim only) to change the directory for the current tab.
+
 ------------------------------------------------------------------------------
                                                          *'NERDTreeChDirMode'*
 

lib/nerdtree/path.vim

@@ -74,7 +74,7 @@ function! s:Path.changeToDir()
     endif
 
     try
-        execute "cd " . dir
+        execute g:NERDTreeChDirCMD . dir
         call nerdtree#echo("CWD is now: " . getcwd())
     catch
         throw "NERDTree.PathChangeError: cannot change CWD to " . dir

plugin/NERD_tree.vim

@@ -49,6 +49,7 @@ call s:initVariable("g:NERDTreeCaseSensitiveSort", 0)
 call s:initVariable("g:NERDTreeNaturalSort", 0)
 call s:initVariable("g:NERDTreeSortHiddenFirst", 1)
 call s:initVariable("g:NERDTreeChDirMode", 0)
+call s:initVariable("g:NERDTreeChDirCMD", "cd")
 call s:initVariable("g:NERDTreeCreatePrefix", "silent")
 call s:initVariable("g:NERDTreeMinimalUI", 0)
 if !exists("g:NERDTreeIgnore")