pypi-mirror creates a separate mirror index for wheels (one per OS
that mirrors are built on). To be able to use it one then needs to be
able to export multiple mirrors for inclusion in pip.conf. As a drive
by I made it possible to disable the use of the pypi.python.org index
without using --offline (as --offline has larger impact).
Change-Id: I3e85a8069b18cafd7eae4cd0591821acc3b5a739
The pypi element is cool, but some folk have local network mirrors
which we should permit them to use.
Change-Id: Ie840ad1184e72b0e01966eee0298cfd6511b6c19
Using a custom pypi mirror can be very convenient, making image builds
substantially faster - because we create multiple virtual
environments we benefit more than single-virtualenv users would.
Change-Id: I997daf1f9477c447e1fb30818aea9e80a49b31a6
