* Issue was detected whilst testing 0.4.0 from @Waterdrips which
added basic auth, but the header was not being propagated.
* This code is tested in OpenFaaS already, but unit tests will
be added retrospectively.
* Proxy now reads the gateway URL via a channel instead of from
a file to make unit testing easier.
Basic auth now works as expected with faas-cli login / list.
Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>
