Fix key handling in Firefox

scripts/game.js

@@ -116,7 +116,7 @@ var MainMenu = new Scene();
 var PauseScreen = new Scene();
 (function() {
   var onKeyUp = function(e) {
-    switch(e.keyCode) {
+    switch(e.charCode) {
       case 81:
       case 113:
       case 27:

scripts/games/safari.js

@@ -464,7 +464,7 @@ function SoundSafari(beatInfo) {
   };
 
   var onKeyUp = function(e) {
-    switch(e.keyCode) {
+    switch(e.charCode) {
       case 80:  // P
       case 112: // p
       case 32:  // space