Support for gulp-reporter #129

We all know that code-style checking is very important, but most of the opposition is that the introduction of stylelint and other tools can cause such a problem:
A few lines of code are modified by a file in the project, and stylelint will prevent you commit the entire file.
Based on this very necessary reason, I developed gulp-reporter.

But for a long time, I have been unable to compatible with gulp-postcss, can the result of postcss external to file object?

See: https://github.com/postcss/gulp-postcss/pull/106/files#diff-168726dbe96b3ce427e7fedce31bb0bcR71