feat(themes): theme builder app updates

* theme-builder wip

* Theme Builder updates
- new CSS variable support
- realtime color updating with alpha support (rgb generation)
- auto tint/shade/contrast generation
- auto step generation
- CSS variable highlighting (forward and backwards)
- Colourlovers Palette search (via local proxy)

packages/core/scripts/theme-builder/stencil.config.js

@@ -8,4 +8,4 @@ exports.devServer = {
   root: '../../',
   watchGlob: 'src/**',
   openUrl: '/theme-builder'
-}
+};