2.2.1

sass code overhaul

Major refactoring of the sass code structure. Here are the consequences:

• should prevent "You may not extend an outer selector from within media" errors (sass-node >3.7.x) thanks to accessible mixin definitions
• makes the "namespaced | global" distinction null and void: framework adapts itself
• any element now implements a enabled: true|false theme variable

Note: should not contain any breaking change (unless mistakes were made) as of now, but both lucca-ui.namespaced.scss and lucca-ui.global.scss files should eventually merge into one as they are now identical and a breaking change it will be.