title: 'sep' parameter not working in sliderInput (Shiny 0.14)
body: <p>after upgrading to Shiny 0.14, the <code>sep</code>parameter in sliderInput does not work for me anymore (although I am not 100 percent sure that upgrading is really the reason).</p>
  
  <p>When I want to use a sliderInput widget for years, I obviously do not want to have any thousand separators. So I tried this in a minimal example:</p>
  
  <pre><code>shinyApp(
    ui = basicPage(
      sliderInput("test", label = "Test slider", min = 1953, max = 2014, step = 1, sep = "",
              value = 1990)
    ),
    server = function(input, output) {
    }
  )
  </code></pre>
  
  <p>And this is what I get on my system:</p>
  
  <p><a href="https://i.stack.imgur.com/vx3AP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vx3AP.png" alt="Screenshot of broken &#39;sep&#39; in Shiny 0.14"></a></p>
  
  <p>Is Shiny 0.14 really the reason for this? Or am I doing something wrong? If I exchange <code>sep = ""</code>to <code>sep = ";"</code> (for example), it works the way it should (; is used as thousand separator).</p>
  
  <p>Thanks for your help.</p>
  
  <p>(I am running R 3.3.1 on Mac OS 10.11.6)</p>