title: create multiple shiny widgets with data from uploaded file
body: <p>In <code>shiny</code>, how do you use <code>tagList</code> inside <code>renderUI</code> to create multiple widgets customized with data from an uploaded file?  This idea is referenced <a href="http://shiny.rstudio.com/articles/dynamic-ui.html" rel="nofollow">here</a>, but there doesn't appear to be very good documentation for <code>tagList</code>.</p>
  
  <p>I plan to answer my own question here.  I did a bit of research, found that a simple example of this process was lacking, and felt a desire to contribute it so that others might benefit.</p>