title: Remove a number from a comma separated string while properly removing commas
body: <p><strong>FOR EXAMPLE:</strong> Given a string... "1,2,3,4"</p>
  
  <p>I need to be able to remove a given number and the comma after/before depending on if the match is at the end of the string or not.</p>
  
  <p>remove(2) = "1,3,4"</p>
  
  <p>remove(4) = "1,2,3"</p>
  
  <p>Also, I'm using javascript.</p>