SpikeWars: fix canvas internal size as well as CSS size.

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

@@ -14,7 +14,7 @@
   <body>
     <div id=spike-wars>
       <h1>Spike Wars!</h1>
-      <canvas></canvas>
+      <canvas width=960 height=384></canvas>
     </div>
     <script type='application/javascript' src="js/spike-wars-${version}.js"></script>
   </body>