Added Learning Lab 3, WebRTC Data Channel.
Fixed typo from LL2.
Add in app-ified page for web rtc data learning lab
Quick fix
Merge pull request #120 from rossbruniges/dev

Adding in resource template for new learning web RTC data learning lab
Merge pull request #121 from mozilla/dev

Merging up 2nd Web RTC learning lab through dev to staging
Merge pull request #122 from mozilla/stage

Merging up 2nd Web RTC learning lab through staging to live