fix(controller): inject config on top of existing environment
fix(controller): do not commit to latest

while this was a nice-to-have before, we are actually pushing config
values on top of the latest build, which breaks config:unset.
fix(controller): use build tag if present
feat(builder): inject GIT_SHA into builder apps
fix(builder): use proper dockerfile syntax
chore(release): update version to v0.13.1
chore(*): bump CoreOS to 471.1.0
feat(client): add auth:whoami

This adds a new command to the client which will display the current
user who is logged into the deis controller.
test(integration): add auth:whoami test
ref(builder): remove python and jq from the builder script. replaced by small go apps.