Better :messages log

[jordwalke]

Here's a proof of concept for Atom's notifications that get rid of the spammy user experience of Atom's notifications. It would be cool to render Vim's :messages log in this manner:

atom/notifications#29

[bryphe]

Cool design, I hadn't seen it before, I like the idea a lot! It's nice to be able to opt-in to getting barraged with all the details. Would make a lot of sense to integrate in terms of messages, errors, etc.

I believe this RFC will make it easier to get at the messages:
neovim/neovim#5686

[bryphe]

This PR neovim/neovim#7466 looks like it could help us here too-