Add support for other (non-V8) trace formats

[mourner]

In theory, it shouldn't be much of a trouble to add support for other trace formats. The common ones I've seen are:

• Perf traces (perf report)
• DTrace ticks
• FlameGraph folded traces (BCC, FlameGraph stackcollapse)
• Perf folded traces (perf report -g folded on Linux v4.5+)
• cpuprofile format used by Chrome Dev Tools?

cc @springmeyer

[rebornix]

I'll suggest to support the output of Chrome Dev Tools JavaScript Profiling.

[mourner]

@rebornix good idea, added to the list. Code for parsing it (for reference): https://github.com/bengl/cpuprofile2stackcollapse/blob/master/index.js