Simplify the example by just displaying the videoUrl (the string value
of which is contained in `dangerousVideoUrl`). We don’t need the URL to
be changeable anymore than we need the dangerousUrl to be editable.
Fixes#3121
* plunker builder removes files and scripts not needed in plunkers (e.g., systemjs.config.js)
* no longer adds placeholder README.md (deemed a distraction)
* tag is now "Angular" instead of "Angular2"
* new plnkr.json "includeSystemConfig" option adds systemjs.config.js back; needed for testing plnkrs.
* incidentally changes comment "Polyfill(s)" to "Polyfills" in all index.html
- App now shows how Angular handles untrusted URLs and resources
- E2e test covered new functionality
- Copyedits to prose
- Updated provider expressions to use latest syntax
The original security feature tracker:
https://github.com/angular/angular/issues/8511
