Provide IDE source-map support for clickable links.

[jamestalmage]

@vojtajina got this issue started with the Intellij folks, and after further discussion I think they are willing to make it a reality. The goal is providing clickable links that will correctly handle Karma's source-map stack trace output.

Initially, I believe all it will require is supplying them with a formal definition of the output, and how to correctly locate files (See my comments in the above youtrack issue - a core karma contributor should make sure I'm not giving bad advice).

We also floated the idea of providing an http download of every intermediate step in the transform chain, so that every portion is clickable. i.e. with: final file <- transform1 <- transform2 <- original file, have each item separated by <- be clickable, with karma serving up the contents at each intermediate state. This would be pretty helpful understanding/debugging what various preprocessors have done to your files.

[dignifiedquire]

As I don't use intelij myself I won't be working myself on this but I'm happy to accelt a PR to help with this and answer questions.