Add overview like FlameScope

[smithamax]

Not sure if you've seen this, netflix open sourced a similar tool today.
https://medium.com/@NetflixTechBlog/netflix-flamescope-a57ca19d47bb
The heatmap overview is really compelling, thought I'd leave it here as an idea.

I might even take a stab at it if I get time... maybe 😝

[mourner]

This is probably out of scope for this project — it's designed to be simple, minimalistic and for generic use, while FlameScope is specifically targeted at finding CPU spikes in mostly idle server applications.