Add proxy support for get_from_cdn

[CloudyAvalon]

Summary

Add proxy support for get_from_cdn in http.py

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[CloudyAvalon]

... I forgot to add param, I ll commit again

[CloudyAvalon]

... I forgot to add param, I ll commit again

[Rapptz]

You don't have to recreate PRs, you can just add commits to a PR by pushing to the branch.

[CloudyAvalon]

You don't have to recreate PRs, you can just add commits to a PR by pushing to the branch.

Thanks, I'm not familiar with pull request.