Custom overlays for apps

Instead of just server channels and chats, it should be possible to see other applications in the overlay, like Chrome or a music app. Instead of alt-tabbing, we can just Shift + ` to see it. It would also be cool to show the tabs when in-game and customize the transparency, similar to the voice channel speakers. This could be good for seeing a build in League of Legends or checking music when playing Minecraft. It can create a community of overlays and help with the new live-streaming feature!