Updated Jest config to work on windows

Signed-off-by: Thomas Florin <thoflo002@gmail.com>

jest-unit.json

@@ -13,6 +13,7 @@
     "object-assign",
     "underscore",
     "source-map-support",
-    "<rootDir>/node_modules/.*JSONStream"
+    "<rootDir>/node_modules/.*JSONStream",
+    "<rootDir>/node_modules/core-js"
   ]
 }