title: Error when running :PlugInstall
body: <p>I want to use vim-plug for managing plugins, but when I run ":PlugInstall" this error is thrown:
  <a href="http://i.stack.imgur.com/5o9wd.png" rel="nofollow">Vim error after :PlugInstall in cmder</a></p>
  
  <p>I only have this in the vimrc file:</p>
  
  <pre><code>call plug#begin()
  Plug 'scrooloose/nerdtree'
  call plug#end()
  
  set ruler
  set number
  
  set laststatus=2
  </code></pre>
  
  <p>I am using Windows 10 x64, cmder as terminal and vim 7.4.827.</p>