moved queue instantiation to avoid unnecessary declaration (mapbox#47)

Author: zbennett10

polylabel.js

@@ -23,11 +23,11 @@ function polylabel(polygon, precision, debug) {
     var cellSize = Math.min(width, height);
     var h = cellSize / 2;
 
+    if (cellSize === 0) return [minX, minY];
+
     // a priority queue of cells in order of their "potential" (max distance to polygon)
     var cellQueue = new Queue(null, compareMax);
 
-    if (cellSize === 0) return [minX, minY];
-
     // cover polygon with initial cells
     for (var x = minX; x < maxX; x += cellSize) {
         for (var y = minY; y < maxY; y += cellSize) {