Add settings

[Semigradsky]

It would be nice to be able to disable some features. IE hacks for example.

Something like

  postcss: [
    cssgrace({
        ieOpacity: false,
        ieInlineBlock: false
    })
  ],

[qikkeronline]

:+1: would be great to be able to turn each feature on or off. really don't need some of them. Thanks!

[ericorruption]

+1

[asavin]

+1 here too, especially on image resizing