Since I use pkg/errors, each error satisfies the fmt.Formatter interface and thus, every error log comes with a cause trace in the errorVerbose field.. This is great in production, but during development, (i.e. with NewDevelopmentConfig), I'd like to see the cause trace in a non-json field so that I can read it.

Right now, the formatting is that it provides several lines, separated by \n which get shoved into the errorVerbose field. Imagine if the stacktrace provided by Zap were to be shoved into a field in development mode. It would be very hard to read.

this issue forked from #650