[vim]Manage NerdTree with vundle

.vimrc

@@ -13,7 +13,8 @@
 "   F8          view tag list
 " S-F8          build ctags/cscope databases
 " M-F8          build kernel ctags/cscope databases
-"   F9          Show diff line
+"   F9          Open NerdTree
+" M-F9          Show diff line
 " S-F9          Highlight diff line
 " M-F10	        diff tool
 "   F10         folding
@@ -422,9 +423,15 @@ colorscheme mycolor
 cnoremap sudow w !sudo tee % >/dev/null
 
 """""""""""
-" gitgutter
+" NerdTree
 """""""""""
-map <F9>   :GitGutterSignsToggle <CR>
+autocmd bufenter * if (winnr("$") == 1 && exists("b:NERDTreeType") && b:NERDTreeType == "primary") | q | endif
+map <F9>   :NERDTreeToggle<CR>
+
+"""""""""""
+" GitGutter
+"""""""""""
+map <M-F9> :GitGutterSignsToggle <CR>
 map <S-F9> :GitGutterLineHighlightsToggle <CR>
 
 """""""""
@@ -465,6 +472,9 @@ Plugin 'MarcWeber/vim-addon-mw-utils'
 Plugin 'honza/vim-snippets'
 Plugin 'garbas/vim-snipmate'
 
+" Filesystem exploration
+Plugin 'scrooloose/nerdtree'
+
 " Python completion
 "Plugin 'klen/python-mode'
 "" Python Bundle