title: Nltk word tokenizer treats ending single quote as a separate word
body: <p>Here's a code snippet from the IPython notebook:</p>
  
  <pre><code>test = "'v'"
  words = word_tokenize(test)
  words
  </code></pre>
  
  <p>And the output is:</p>
  
  <pre><code>["'v", "'"]
  </code></pre>
  
  <p>As you can see the ending single quote is treated as a separate word, while the first one is a part of "v". I want to have</p>
  
  <pre><code>["'v'"]
  </code></pre>
  
  <p>or</p>
  
  <pre><code>["'", "v", "'"]
  </code></pre>
  
  <p>Is there any way to achieve this?</p>