SpikeWars: refactor rendering out into a separate module. Finished with basic game loop.

spike-wars/src/main/html/index.html

@@ -16,6 +16,7 @@
       <h1>Spike Wars!</h1>
       <canvas width=960 height=384></canvas>
     </div>
+    <div><input id=pause type=checkbox checked=false>Pause</input>
     <script type='application/javascript' src="js/spike-wars-${version}.js"></script>
   </body>
 </html>