Adds examples/mirror.html

[DoctorBud]

• Adds 'make run-pretty' option to format log output in a more human-readable way.
• Fixes typos in a couple places
• Adds static/examples/mirror.html, which synthesizes a video source and acts as a peer.
• Adds links to other examples to bottom of static/index.html
• Adds js/mirrormedia.js which uses a Canvas to create a peer video stream.
• In peering.js, add a 1-second delay before manually firing .play() on a newly created video element. This resolves random issues where even an autoplay video element doesn't start playing automatically.