Finally fix TimeStep

lib/App.dart

@@ -6,13 +6,12 @@ import 'package:rules_of_living/Grid.dart';
 class App {
   // Elapsed Time Counter - useful for Safety Timeout
   Stopwatch _elapsed = new Stopwatch();
-  num lastNow = 0;
 
   // Game Tick Rate - *does* impact game speed
   final int _MS_PER_STEP = 1000;
 
   // Max Frame (i.e. Rendering) rate - does *not* impact game speed
-  final int _MS_PER_FRAME = 1000;
+  final int _MS_PER_FRAME = 1000 ~/ 2;
 
   // ms stuck in updateloop after which game will declare itself unresponsive
   final int SAFETY_TIMEOUT = 2000;
@@ -27,13 +26,12 @@ class App {
 
   App(this.canvas) {
     this.map = this.grid.map;
+    _elapsed.start();
   }
 
   void process(num now) {
-    _drawLag = now - lastNow;
-    lastNow = now;
-
-    _updateLag += _drawLag;
+    _drawLag+= _elapsed.elapsedMilliseconds;
+    _updateLag += _elapsed.elapsedMilliseconds;
     _elapsed.reset();
 
     while (_updateLag >= _MS_PER_STEP) {
@@ -59,6 +57,7 @@ class App {
 
 
   void render([num interp]) {
+    print("rendering");
     html.CanvasRenderingContext2D ctx = canvas.getContext('2d');
     int brickW = (canvas.width ~/ map[0].length);
     int brickH = (canvas.height ~/ map.length);