Rebase speed.python.org branch on top of master

[diegorusso]

The branch https://github.com/python/codespeed/tree/speed.python.org has diverged from https://github.com/python/codespeed/tree/master.

We should rebase speed.python.org changes on top of master branch.

I tried rebasing it and there are a few conflicts to resolve (nothing major though)

[ambv]

Fixed. Thanks, Diego!