Remote Playback API spec

Hi all!

I encourage you to take a look at the current version of the Remote
Playback API spec <https://w3c.github.io/remote-playback/> [1]. I believe
the spec is in a good enough state for an initial review by the group.

Please, note that the F2F taking place in a week will start
<https://www.w3.org/wiki/Second_Screen/Meetings/May_2016_F2F#Agenda> [2]
with the discussions about the Remote Playback API so now might be a good
time to have a preview for context.

If you find any issues, please file them on GitHub
<https://github.com/w3c/remote-playback/issues> [3] if they're not there
already. Also use this thread and/or mailing list for discussions.

Thanks,
Anton & Mounir.

[1] https://w3c.github.io/remote-playback/
[2] https://www.w3.org/wiki/Second_Screen/Meetings/May_2016_F2F#Agenda
[3] https://github.com/w3c/remote-playback/issues