Output source files and lines to JSON

[tmeasday]

This commit ensures that the json dump includes information about source locations.

[blakeembrey]

FWIW, this coding style is kind of terrible but since it matches the existing style I'll merge it as is. The preferred way to write this would be using Array#map.

[aciccarello]

@blakeembrey, the entire codebase probably should be reviewed and a tslint configuration added. It would be a lot of work but possibly a good way to someone who wants to take on #256 to get a good handle on the codebase.

[blakeembrey]

Absolutely, I agree - there's a lot I'd love to refactor - it's just not in a state where I can actively maintain it. The codebase is takes advantage of too much fanciness for me to focus on how it actually works (decorators, indirect dependencies, etc). I can get a gist, but without rewriting I'm not comfortable maintaining it myself right now 😄