WIP: Migrate circuits.web HTTP components to `httoop`

[spaceone]

Fixes #288

I made a proof of concept some time ago and didn't have the time yet to finish it. But it gives a impression.

@prologic @Osso @kromg @justingiorgi @eriol @apollo13 Could you read the issue #288 and give a opinion on this?

[eriol]

Hi, thanks for your effort on this. I hope to have the time look more deeply but after a fast look I would like to suggest only one thing. If we add in setup.py something like

install_requires=['httoop'],

we will be able to continue to pip install citcuits without the need to install manually httoop.

[spaceone]

All tests are passing :-)