Add browser tests via karma

package.json

@@ -13,11 +13,20 @@
     "gulp-tslint": "^8.1.2",
     "gulp-typescript": "^3.2.3",
     "tslint": "^5.8.0",
-    "typescript": "^2.6.2"
+    "typescript": "^2.6.2",
+    "webpack": "^3.10.0",
+    "karma": "^2.0.0",
+    "karma-jasmine": "^1.1.1",
+    "karma-chrome-launcher": "^2.2.0",
+    "karma-firefox-launcher": "^1.1.0",
+    "karma-webpack": "^2.0.9",
+    "karma-sourcemap-loader": "^0.3.7",
+    "ts-loader": "^3.3.1"
   },
   "scripts": {
     "test": "gulp test",
-    "lint": "gulp lint"
+    "lint": "gulp lint",
+    "browser-test": "karma start --single-run"
   },
   "repository": {
     "type": "git",