[ECO-123] - Switched out demo-html recommendation with Playground (#34)
[ECO-123] - Switched out demo-html recommendation with Playground (#34)

* Switched out demo-html recommendation with Playground 

removed reference to html demo file

* Update README.md

opentok/opentok-ios-sdk-samples-swift,opentok/opentok-ios-sdk-samples-swift,opentok/opentok-ios-sdk-samples-swift