Fixed #2560: IE11 issue 'Symbol' is undefined with babel-polyfill (#2566)

* address IE11 issue 'Symbol' is undefined with babel-polyfill  

https://github.com/almende/vis/issues/2560

* address IE11 issue 'Symbol' is undefined with babel-polyfill

https://github.com/almende/vis/issues/2560

* address IE11 issue 'Symbol' is undefined with babel-polyfill

https://github.com/almende/vis/issues/2560

.babelrc

@@ -2,6 +2,7 @@
   "presets": ["es2015"],
   "plugins": [
     "transform-es3-property-literals",
-    "transform-es3-member-expression-literals"
+    "transform-es3-member-expression-literals",
+    "transform-runtime"
   ]
 }

package.json

@@ -29,6 +29,8 @@
     "watch-dev": "gulp watch --bundle"
   },
   "dependencies": {
+    "babel-polyfill": "^6.20.0",
+    "babel-runtime": "^6.20.0",    
     "emitter-component": "^1.1.1",
     "moment": "^2.12.0",
     "propagating-hammerjs": "^1.4.6",
@@ -41,6 +43,7 @@
     "babel-loader": "^6.2.10",
     "babel-plugin-transform-es3-member-expression-literals": "^6.8.0",
     "babel-plugin-transform-es3-property-literals": "^6.8.0",
+    "babel-plugin-transform-runtime": "^6.15.0",
     "babel-preset-es2015": "^6.18.0",
     "babelify": "^7.3.0",
     "clean-css": "^3.4.10",