title: Not getting Vim to autoload files in ftdetect custom plugin project
body: <p>The example I am following is from the book The VimL Primer Chap 4.</p>
  
  <p>In the <code>ftdetect</code> dir I have the following line:</p>
  
  <pre><code>autocmd BufRead,BufNewFile *.mpdv set filetype=mpdv
  </code></pre>
  
  <p>In a file called mpdv.vim</p>
  
  <p>However this command is not executed when I open a mpdv file.
  In .vimrc I have:</p>
  
  <pre><code>filetype plugin on
  </code></pre>
  
  <p>The way im loading the plugin is the following:
  In ~/.vimrc I have:</p>
  
  <pre><code>set exrc
  </code></pre>
  
  <p>This forces vim to load local .vimrc files</p>
  
  <p>Then in my projects pluginfolder i have the follwoing .vimrc</p>
  
  <pre><code>set runtimepath+=path/to/my/plugin
  </code></pre>
  
  <p>What can I do the debug why vim is not loading my autocmd when I open a mpdv file?</p>