Feature Request: Enable selecting a formatter in format function

[nirazul]

I'm not sure where to put this, either here or at sass-lint, correct me if I'm wrong:
It'd be neat to have an argument in gulpSassLint.format to choose the formatter on the fly rather than choosing it in the options.

The background is that I'd like to format the output twice, once with the stylish formatter, and then again with a custom formatter (as a function) to report it via browser-sync to the window:

    gulp.src(myFiles)
            .pipe( $.eslint() )
            // Log errors
            .pipe( $.eslint.format('stylish') )
            // Format errors
            .pipe( $.eslint.format(myCustomFormatterFunction) );