Make transitive transforms & resolves possible

[mfal]

Issue #208

Transformations can only be executed, if the value to be transformed, has no references in it. So resolving may lead to enable further transformations, and sub sequent resolving may enable even more transformations - and so on.

Unfortunately the current implementation only transforms and resolves once, and transformation on values containing references do not work. This change enables this transitive dependencies, by executing "transform & resolve" until all transformations are executed.

Take the following example (the color: {...} object might setup your custom color transformation)

color.brand = {
  value: "{color.base.green}"
}

color.background.button.primary.base = {
  value: "{color.brand.value}",
  color: {
    desaturate: 0.5
  }
}

color.background.button.primary.hover = {
  value: "{color.background.button.primary.base}",
  color: {
    darken: 0.2
  }
}

As you can see color.background.button.primary.hover is a variation of color.background.button.primary.base which is a variation of color.base.green. This transitive dependencies are solved by running this loop.

[dbanksdesign]

Thank you for submitting this! This is a pretty big PR, it'll take some time to review. Please have some patience on this.

[dbanksdesign]

Hey @mfal ! Sorry it took so long to get to this, it has been a busy few months. I finally dug into this PR and we are super excited to get this into the next major release (3.0). I made some changes/proposals and created a pull request on your branch, https://github.com/mfal/style-dictionary/pull/1. Let me know what you think and when that gets merged in, this PR should automatically update and we can merge it in. Let me know if you have any questions/concerns.

Thank you so much for this contribution!