Suiggestion: use inferno for flamegraphs

[jonhoo]

Now that inferno is relatively stable, and exposes separate APIs for both stack folding and producing flamegraphs, I wonder if it'd be interesting to see if we could make flame use inferno to generate the flamegraphs. That way you wouldn't need to vendor all the JS code and such into this project. You'd also get stack folding for free if you wished!