code: function calcSortedIntersections(lines,y) {
      var xlist = [];
      for(var i=0; i<lines.length; i++) {
          var A = lines[i].start;
          var B = lines[i].end;
          if(A.y<y && B.y>=y || B.y<y && A.y>=y) {
              var xval = A.x + (y-A.y) / (B.y-A.y) * (B.x-A.x);
              xlist.push(xval);
          }
      }
      return xlist.sort(function(a,b) {  return a-b; });
  }
docs: Calculate Sorted Intersections
  
  Adopted from http://alienryderflex.com/polygon
  
  @see http://alienryderflex.com/polygon
  
  @param {Array} lines An {@link Array} of Lines
  @param {number} y
  
  @ignore
  
  @returns {Array}