Improve logic of local/remote video views

[atsakiridis]

Right now, to avoid bad experience the user app needs to hide the views until RCConnection is connected and then show them. If we show them earlier, they show up black and hide all content in the page.

Instead, what we should do is the following:

• Start off with video views hidden (from the layout)
• Improve the SDK to handle showing the views as soon as there is content for them (i.e. when PeerConnection notifies us)
• Make the local video take up all screen until remote is available (if it is available)
• Provide RCConnection events for when local & remote video is ready. Seems like something the App might be interested about

Generally the local video should always reflect the user's choice of call (either calling or answering). That way they know if they are visible in the other side

[atsakiridis]

This still feels a bit off :( Muting local video while in call totally removes the remote view which I'm not sure if it's a good idea.

The thing here is that we don't want the full screen view to ever get black and for that reason if hide the view completely.

Also we want the local video to show up full screen until the remote joins, as it looks pretty bad to have just a small video on the top right and the rest of the screen show the olympus logo.

Let's reopen and revisit at BETA5 release since it's minor