General improvements

sources/index.html

@@ -22,7 +22,7 @@
 
       var keyboard = new Keyboard();
 
-      document.onkeyup = function myFunction(event){ keyboard.listen(event); };
+      document.onkeydown = function myFunction(event){ keyboard.listen(event); };
       document.addEventListener('mousedown', function(e){ dotgrid.mouse_down(e); }, false);
       document.addEventListener('mousemove', function(e){ dotgrid.mouse_move(e); }, false);
       document.addEventListener('mouseup', function(e){ dotgrid.mouse_up(e);}, false);