Kill preprocessor

[simonsmith]

Most of the features in there have native browser support already, and it's very easy to hook up postcss-cli otherwise.

Either that or we could create a plugin pack, similar to this.

[giuseppeg]

+1 for creating the preset

[mlnmln]

Agreed. From a consumers' perspective it's more transparent to depend on a preset.

Edit: We should either create a plugin pack or consider just adopting postcss-preset-env https://github.com/csstools/postcss-preset-env. Which would stay true to the "future facing CSS" paradigm, would'n it?