ref(client): use logging module; add colors to `deis logs`

With this change, we can now have more power over how we filter and
deal with our logs in the client. This change prints everything with log level WARNING and above into STDERR and everything lower into STDOUT. The output of the client commands stay the same.

I've also added another feature on top of this PR to add colorized logs :)
Maybe we should add a TODO or FUTURE here? It may trip up other people when reading the code, wondering why we're setting levels to debug.