purgecss-webpack-plugin 1.0.0

[zhenbinjing]

I suggest replacing extract-text-webpack-plugin with mini-css-extract-plugin

[jsnanigans]

Hey, that's a great idea, ill add it to the webpack-4 branch when I get a moment and when webpack 4 is more commonly used Ill replace the master

[jsnanigans]

I will close this issue for now, when mini-css-extract-plugin supports HMR I will replace extract-text-webpack-plugin,
thank you for the suggestion