Support multiple file sourcemaps

[agg23]

It would be very useful if you could provide a folder of sourcemaps, that way you don't have to run the command for each file in chunked build scenarios.

[mifi]

I'm not sure how this would work. Can one stack trace originate from multiple source maps? How does stacktracify know which source map the stack trace is from?

[agg23]

I can't find a good exception stack example trivially, but Webpack and similar bundling systems allow for emitting multiple "chunks", each with individual source maps. These stack traces identify which browser resource (i.e. *.chunk.js) the line in question comes from.

[askarby]

I created a PR for this #5