Make pip install / easy_install faster

[methane]

pip install ipython scrapes some website.
http://pypi-externals.caremad.io/ipython/

Setting PyPI makes install faster.
http://pypi-externals.caremad.io/help/what/

[takluyver]

Thanks, that makes sense. I'd like to leave a bit of time for people to weigh in. pip lets you specify a version, are there any special cases we need to make sure still work? I've just tested pip install ipython==dev, and that doesn't work (it still tries svn).

[takluyver]

I've had a bit more of a look into this. It's scraping several pages, so we should get a nice speedup in installation by doing this. It's also good for security: as PEP-438 points out, anyone who can do an HTTP man in the middle attack could currently deliver malicious code to a user trying to install IPython.

Users would no longer be able to pip install ipython== dev (which doesn't work anyway), 0.9.1, 0.9 or 0.8.4. Of course you could still manually download and install them if you had a particular need, so I'm not too worried that the automated installer tools won't find those old versions.

That seems like a no-brainer, so I've gone ahead and flipped the switch. We can flip it back if we find problems.