Prior to this commit, experimental flags were not distinguishable from
regular flags in `--help`
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
ReadLocalFiles should allow passing the stdin file as an argument, which
allows us to read from dockerCli.Stdin() to be consistent with other
commands in the same package.
Signed-off-by: Justin Chadwell <me@jedevc.com>
