added jest to package.json

Author: hs

package.json

@@ -43,6 +43,7 @@
     "grunt-tslint": "^4.0.1",
     "grunt-typedoc": "^0.2.4",
     "grunt-webpack": "^3.1.2",
+    "jest": "^23.4.2",
     "tslint": "^4.5.1",
     "typedoc": "^0.11.1",
     "typescript": "^2.9.2",