Update repositories to quay.io
Install python-pip for the gecko-b2g-builder.

For some reason it builds fine locally, but fails on quay.io without it.
Quiet b2g pulls for smaller logs
Split b2g-build/build-setup.sh into multiple RUN commands.

This should help split up the main layer into a smaller B2G layer and a
gecko layer (for certain values of small).
Consistent naming of 'builder' and 'b2g-builder'
Merge pull request #11 from mshal/b2g-build

quay.io changes for b2g builds