Support requests>2.5.0

[vmalloc]

Currently docker-compose cannot be installed for virtualenvs containing newer requests installations

[dnephin]

This was previously being blocked by docker-py, but it looks like that was fixed in docker/docker-py@9bed480 (docker-py 1.1.0).

[vmalloc]

Ok, so can it be released please please pretty please?

[dnephin]

If you submit a pull request, I will do my best to get it in.

[vmalloc]

Created #1100

[aanand]

Closed by #1100.