Wrangle dependency madness

[schrockn]

So we need to figure out a short term dependency strategy for our 0.5.0 release.

I suggest a few principles

1. Our setup.py dependencies should as loose as possible
2. Our dev environment should be as strict as possible.

This means we should have separate snapshot requirements.txt files that act as our lockfiles for local dev and test runs. This would prevent redownloading the world with our integration images. However we want to be permissive with our user base and not incur dep hell on them.

#1273

[natekupp]

Punting from 0.5.0

[natekupp]

Marking as dupe, let's use #1295 as the primary issue for this