Updated Native app styleguide CSS/JS files

New files for CSS Framework:
https://d35z3p2poghz10.cloudfront.net/ecwid-sdk/css/1.3.19/ecwid-app-ui.css
https://d35z3p2poghz10.cloudfront.net/ecwid-sdk/css/1.3.19/ecwid-app-ui.min.js

Added new elements (color swatches, color cards, chips), minor improvements and fixes.