Exit with code 1 when cmd.Run() returns error

[liuxh0]

As discussed in #8, I think this is the way we want it, right?

[liuxh0]

BTW I used go get ./... and godep restore to download dependencies. It seems the v2 of github.com/urfave/cli is downloaded. Therefore I got a lot of compile errors because of type mismatch. Manually changing to v1 branch fixes the problem.

Shouldn't the version of github.com/urfave/cli go into Godeps.json?

[herrjulz]

Hi @liuxh0 , sorry for my very late response and thank you for your PR. The PR looks good. I'll check the issue with the dependencies.