Add support for autoprefixer

[bjmiller]

Mincer supports autoprefixer out of the box as a processor. Can we include that seamlessly, so it runs after converting from LESS/Stylus, and before minification?

[matheusazzi]

+1. There is a way to do this?

[adunkman]

PRs are welcome! :)

[adunkman]

You can now (as of v4.6.0) pass a second argument to the function returned by require("connect-assets") to specify custom configuration of Mincer as connect-assets is starting up — custom configuration, like turning on autoprefixer.

1. You’ll need the autoprefixer-core module.

2. Enable autoprefixer within the Mincer environment:

   app.use(require("connect-assets")(options, function (instance) {
     instance.environment.enable("autoprefixer");
   }));