Setup cleanup with requirements hierarchy

I've observed a pattern with requirements files, and they are starting to stay out of sync.

Pip requirements files can be referenced from others files. You only have to include a line starting with `-r` followed by another requirements filename.

So, I did the diff between files and cleaned duplicated requirements.

```
requirements.txt (base)
|-------- requirements_test_osx.txt  (requirements.txt + test/develop dependencies)
|        |--------- requirements_test.txt (all above + wsgiref)
```