add unparam linter?

[ryboe]

unparam is one of the few gometalinter linters missing from golangci-lint. It catches unused function parameters. I don't know if it's worthwhile. Maybe that functionality is already handled by another linter? I'd like to hear from golangci about whether this is worth adding. Thanks!

[jirfag]

hi,
supported unparam in #141

[ryboe]

You're my hero, dude.