Use lowercase f in formatting function names

[chr4]

Your project looks really nice!

When reading the examples, I propose to streamline function names to correspond to the naming scheme of fmt, log and testing: fmt.Printf(), log.Printf(), t.Errorf() are all using lowercase f, whereas your package uses WarningF() DebugF() with capital Fs.

Proposal: Use lowercase f in your package as well, e.g. Warningf()

[apsdehal]

We have them already. See https://github.com/apsdehal/go-logger/blob/master/logger.go#L356 and related functions. Closing for now as "already exists".