title: Manually set color for venn diagrams in Vennerable package
body: <p>Hi I would like to be able to manually assign the colors. 
  For example </p>
  
  <pre><code>library(Vennerable)
  data(StemCell)
    w &lt;- Venn(Sets=StemCell[1:2])
    plot(w, type="squares")
  </code></pre>
  
  <p>produces 
  <a href="https://i.stack.imgur.com/WkAIP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WkAIP.png" alt="enter image description here"></a></p>
  
  <p>however what I would like to do is manaully change the color, OCT4=red, overlap=brown and Sox2=green? 
  is this possible with the current package?  I tried setting gpar but it did not appear to do anything in particular. </p>
  
  <p>thanks!
  A</p>