Fixes to get token colour definitions to work.

[obscherler]

• Fix the path in the build-tokens script so that tokens are processed;
• Fix the structure of the token file so that colour definitions are taken into account;
• Change the usage of the --pgn-color-primary variable to --pgn-color-primary-base so that the variables defined by the token file have an effect.

I think if the SCSS variables were replaced with the paragon replace-variables command instead of manually, with an adequate token file, it would have been automatic (color.primary.base has "source": "$primary", so $primary would be replaced by --pgn-color-primary-base.)

[obscherler]

Please disregard, I started over in #43 and got much further.