Make using revealjs-swiss colors easier

[mirdaki]

Right now you basically need to download the whole Reveal.js code (on the gh-pages branch) and recompile to switch to one of the other Revealjs code options. I see two ways to improve this without making the source messy.

1. Have the SCSS generate separate CSS files for each color option, without having to copy and paste any of the SCSS. This way people just download the CSS file they want and update one line of HTML. This is the preferred way in my mind, though I don't know how to do it.
2. Have a separate SCSS/CSS file with just the colors that can be used with the default generated CSS file to update the color (so modifying two lines of HTML to import them both). I also don't know how to do this, as the SCSS variables aren't available at that point

I am certainly open to suggestions