title: How to find available timezones in a country using momentjs
body: <p>I would like to retrieve a list of timezones with utc offsets from momentjs by country name. For example, I would like to have something like</p>
  
  <pre><code>   momentObject.getTimezones("America")
  </code></pre>
  
  <p>Which would return a list of timezones like</p>
  
  <pre><code>   ['UTC−11:00 (ST) — American Samoa, Jarvis Island, Kingman Reef, Midway Atoll, Palmyra Atoll',
      ....
  </code></pre>
  
  <p>Does functionality like this exist in the library?</p>