downgrade to coffeescript v1

Author: smhg

package.json

@@ -11,7 +11,7 @@
     "grunt": "^1.0.3",
     "grunt-browserify": "^5.3.0",
     "grunt-cli": "^1.3.1",
-    "grunt-contrib-coffee": "^2.0.0",
+    "grunt-contrib-coffee": "^1.0.0",
     "grunt-mocha-test": "^0.13.3",
     "jsdom": "^13.0.0",
     "mocha": "^5.2.0"