v0.4.1 Release

Merge pull request GoogleContainerTools#81 from aaron-prindle/cobra-args

updated cobra and switched some code to use Args concept

Merge pull request GoogleContainerTools#81 from aaron-prindle/cobra-args

updated cobra and switched some code to use Args concept

Merge pull request GoogleContainerTools#23 from abbytiz/ReadMeKnownEr…

…rUpdate

Adding known issue of etc/docker/certs documentation.