title: Vim Nerdcommenter custom delimiters does not work
body: <p>I am attempting to follow the advice here:</p>
  
  <p><a href="https://stackoverflow.com/questions/4481070/vim-nerdcommenter-adding-a-new-filetype-in-vimrc">Vim NerdCommenter: adding a new filetype in vimrc</a></p>
  
  <p>and here:</p>
  
  <p><a href="https://stackoverflow.com/questions/15303176/macvim-nerdcommenter-how-to-specify-alternative-delimiters">MacVim NERDCommenter, how to specify alternative delimiters</a></p>
  
  <p>When I declare my own CustomDelimiters in my <code>.vimrc</code> file, the Nerdcommenter does not appear to recognize them. </p>
  
  <p>I have put the lines</p>
  
  <pre><code>let g:NERDCustomDelimiters = {
      \ 'blahblah': { 'left': '#'}
  \ }
  </code></pre>
  
  <p>Into my <code>.vimrc</code>, but whenever I open a file called <code>a.blahblah</code>, I still get the default <code>/*...*/</code> commenting behavior. If I attempt to use <code>&lt;Leader&gt;ca</code>, I am told </p>
  
  <p>"NERDCommenter:Cannot use alternative delimiters, none are specified"</p>
  
  <p>I have moved the above lines to the head and tail of my <code>.vimrc</code> file, but I get the same behavior. </p>
  
  <p>Thank you for your help. </p>