Upgrade TypeScript (#148)

* Update typescript to 3.6.5 along with tslint to latest.

* Upgrade @types/node to 12.12.54 to get rid of compile errors.

* Update tslint.

* Use @types/node 10.17.28 instead

package.json

@@ -30,7 +30,7 @@
     "@types/jasmine": "^3.3.12",
     "@types/lowdb": "^1.0.5",
     "@types/lunr": "^2.3.3",
-    "@types/node": "^10.9.4",
+    "@types/node": "^10.17.28",
     "@types/node-fetch": "^2.1.2",
     "@types/node-forge": "^0.7.5",
     "@types/papaparse": "^4.5.3",
@@ -57,9 +57,9 @@
     "karma-typescript": "^4.0.0",
     "nodemon": "^1.17.3",
     "rimraf": "^2.6.2",
-    "tslint": "^5.12.1",
+    "tslint": "^6.1.3",
     "typemoq": "^2.1.0",
-    "typescript": "3.2.4"
+    "typescript": "3.6.5"
   },
   "dependencies": {
     "@angular/animations": "7.2.1",