I've been working with OpenERP (now Odoo) for a long time. But now I'm a little bit confused. I used to inherit point_of_sale and add css on __openerp__.py. But now that it changed and now css files are called inside html_template under point_of_sale/controllers/main.py and also js files are inserted on point_of_sale/views/point_of_sale.xml I am really confused about how this works and how should I add css from my multiple POS addons. I don't want to override and add my css because this should be inheritable. So please can someone explain me how this works?