Compatibility with postcss-cli --watch

[stefanfisk]

I was just wondering if there has been any thought put into compatibility with the --watch mode in PostCSS-CLI?

I can't say that I really understand the architecture of PostCSS, having only used it for the last 12 hours, but might it all start working if we push messages for each scanned content file? postcss-import does it here for example: https://github.com/postcss/postcss-import/blob/master/index.js#L198.