Bring more of the web into your spaces by pasting in songs, albums, and document links.
Implementation Notes
This replaces the previous youtube-only embed support with a general solution that works for any site supported by iFramely.
The reason you have to click play to start the embed is primarily for privacy and performance reasons. When loaded, most embeds execute dozens of tracking scripts. The last thing I want is for spaces to slowdown as you add links to them.