Let scrutiny begin

@RichardLitt @noffle @dignifiedquire can you CR the code please?

After finishing here, I'll bring https://github.com/diasdavid/registry-static to be part of the project instead of a dependency that gets run as a shell command, so that I can get more interesting stats and control of what it is doing.

There is a note on the README important to be able to run the tests https://github.com/diasdavid/registry-mirror/tree/refactor/the-big-clean-up#development

Will check!

I don't understand; what does this PR do?

@diasdavid left some preliminary comments. Also travis is unhappy

@diasdavid: could we get some more context? What are the high-level goals of this refactor?

@dignifiedquire thank you for the CR, I've pushed changes following you comments :)

@RichardLitt @noffle Apologies for not being clear, this PR is the transformation of registry-mirror from a collection of hacks and glue to it all work to a more structured code base, where there is order, making contribution and debugging easier

@dignifiedquire travis is unhappy due to the missing 0.4.0 binary :)

Will move ahead and merge this one, to be able to go to the next step, merge registry-static into the mix :)