Switch over to using sinon.sandbox in karma specs

test/spec/specHelper.js

@@ -1,5 +1,15 @@
 beforeEach(module('habitrpg'));
 
+var sandbox;
+
+beforeEach(function() {
+  sandbox = sinon.sandbox.create();
+});
+
+afterEach(function() {
+  sandbox.restore();
+});
+
 specHelper = {
   newUser: function(){
     var buffs = {per:0, int:0, con:0, str:0, stealth: 0, streaks: false};