refactor: Replace q with bluebird.

[dignifiedquire]

Bluebird is faster, more spec compliant and has a much better set of built in tooling.

Replaces #1440

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[dignifiedquire]

I signed it!

[dignifiedquire]

@zzo after I have merged this, I will start with the refactoring of file_list.js on the canary branch, that way we can hopefully ship it together with 0.13

By the way I'm still missing write access to this repo since this morning :(

[zzo]

lemmie now when the canary is pushed to npm :)