Poll.deleteAll ()
function loops over the choices of a poll and removes them

Sourcecode in Poll/objectFunctions.js:
1:   function deleteAll() {
2:      for (var i=this.size();i>0;i--) {
3:         var c = this.get(i-1);
4:         c.deleteAll();
5:         c.remove();
6:      }
7:      return true;
8:   }