Persistent flags completions

[fabianofranz]

Inherited flags should also be part of completions for every command that inherits it. Also allows marking persistent flags as required or filename for completions.

[CLAassistant]

All committers have accepted the CLA.

[fabianofranz]

@eparis PTAL

[eparis]

gimmie some _test.go. But it seems ok/good/right

[fabianofranz]

@eparis added some.

[fabianofranz]

@eparis circleci failure seems unrelated.

[spf13]

merged as 7290a94.

Yes, circle is unrelated and I've already contacted them about it.

[anthonyfok]

The CircleCI failure seems to be the same as Travis CI build failure:

=== RUN TestRunnableRootCommandNilInput-2
--- FAIL: TestRunnableRootCommandNilInput-2 (0.00s)
    cobra_test.go:667: Execute() failed with unknown shorthand flag: 't' in -test.v=true
    cobra_test.go:671: Root Function was not called

It is triggered by the use of -v flag for go test. Please see #155 for a potential solution.

[anthonyfok]

Forgot to say: @fabianofranz, this is awesome! :-) Now bash completion for Hugo works quite a bit better indeed, e.g. the --watch in hugo server --watch can now be tab-completed. :-)
Many thanks!

[fabianofranz]

👍