title: Cannot upload multiple files on Mac using fileInput
body: <p>Using <code>fileInput()</code> to upload multiple files does not work on Mac. It works on Windows and Linux. I have also set argument <code>multiple=T</code>, but I am not able to select more than one file. Here is a working script.</p>
  
  <pre><code>library(shiny)
  
  runApp(list( 
  ui = bootstrapPage( 
  tags$h2("Upload test app"), 
  fileInput("finput","Upload files",multiple=TRUE), 
  tableOutput("contents"), 
  ), 
  server = function(input, output) {
  
  output$contents &lt;- renderTable({ 
  input$finput}) 
  
  } 
  ))
  </code></pre>
  
  <p>Thanks.</p>