Interaction tracking follow up (#13509)

* Merged interaction-tracking package into react-scheduler
* Add tracking API to FB+www builds
* Added Rollup plugin to strip no-side-effect imports from Rollup bundles
* Re-bundle tracking and scheduling APIs on SECRET_INTERNALS object for UMD build (and provide lazy forwarding methods)
* Added some additional tests and fixtures
* Fixed broken UMD fixture in master (#13512)

Author: bvaughn

package.json

@@ -17,7 +17,8 @@
   "dependencies": {
     "object-assign": "^4.1.1",
     "prop-types": "^15.6.2",
-    "react-is": "^16.4.3-alpha.0"
+    "react-is": "^16.4.3-alpha.0",
+    "react-scheduler": "^0.1.0-alpha-1"
   },
   "peerDependencies": {
     "react": "^16.0.0"