Update sinon to ^2.3.0

Author: papandreou

package.json

@@ -42,7 +42,7 @@
     "magicpen": "^5.12.0",
     "mocha": "^3.4.1",
     "mocha-lcov-reporter": "^1.3.0",
-    "sinon": "^1.17.3",
+    "sinon": "^2.3.0",
     "uglifyjs": "^2.4.11",
     "unexpected": "^10.27.0",
     "unexpected-sinon": "^10.7.1"