Most importantly, in build-ui.bash, fix an extra "&&". This meant
that if the build command fails, it would proceed and cause confusion.
This happened for me: I ran it without the emulation installed. Both
the build-server and deploy stages had problems, but because of the "&&"
the deploy target didn't actually return failure. After I fixed the
emulation problem, there was a bad cached layer.
Also save the build output from the dev stage.