broadcaster interactive plugins

[bengreenier]

Note: requires design proposal and review before implementation

This tracks conversation about how we should support plugins that broadcasters can interact with. This poses an interesting interaction that is not consistent with the primary goals of overlayed - that is, for interactive plugins the broadcaster should be able to click on them. That means that we need a window host that can receive focus and therefore key and mouse events.

I think the implication here is that we must switch window modes often, or maintain yet another electron window.

[bengreenier]

this is important to have though, so we can do plugins for things like twitch chat.