Use :mode only in neovim. MacVim still needs to use :redraw! (#1019)

* Use :mode only in neovim. MacVim still needs to use :redraw!

* Make nerdtree#redraw do both redraw and redraw! based on a parameter.

* Make bang a required parameter.

* Replace all redraw statments with call nerdtree#redraw function calls.

* Update version in change log.

lib/nerdtree/menu_controller.vim

@@ -31,7 +31,7 @@ function! s:MenuController.showMenu()
         let l:done = 0
 
         while !l:done
-            mode
+            call nerdtree#redraw(1)
             call self._echoPrompt()
 
             let l:key = nr2char(getchar())
@@ -42,7 +42,7 @@ function! s:MenuController.showMenu()
 
         " Redraw when "Ctrl-C" or "Esc" is received.
         if !l:done || self.selection == -1
-            redraw!
+            call nerdtree#redraw(1)
         endif
     endtry