Add npm dependencies and script for testing

package.json

@@ -4,6 +4,7 @@
   "description": "React components for OpenTok.js",
   "main": "dist/index.js",
   "scripts": {
+    "test": "karma start",
     "prepublish": "npm run build",
     "build": "babel src --out-dir dist",
     "example": "cd example && browserify -o bundle.js app.js && python -m SimpleHTTPServer"
@@ -28,12 +29,21 @@
   },
   "devDependencies": {
     "babel-cli": "^6.18.0",
-    "babel-preset-react": "^6.5.0",
     "babel-preset-es2015": "^6.9.0",
+    "babel-preset-react": "^6.5.0",
     "babel-preset-stage-2": "^6.18.0",
     "babelify": "^7.3.0",
     "browserify": "^13.0.1",
-    "lodash": "^4.13.1"
+    "enzyme": "^2.6.0",
+    "jasmine-core": "^2.5.2",
+    "karma": "^1.3.0",
+    "karma-babel-preprocessor": "^6.0.1",
+    "karma-browserify": "^5.1.0",
+    "karma-chrome-launcher": "^2.0.0",
+    "karma-jasmine": "^1.1.0",
+    "lodash": "^4.13.1",
+    "react-addons-test-utils": "^15.4.1",
+    "watchify": "^3.8.0"
   },
   "browserify": {
     "transform": [