Changes:
- Dev – Fixed vendors data query when querying by meta data
- Dev – Refactored singleton instance class
- Dev – Added helper function bm_is_vendor_user to check whether user is vendor or not
- Fix – Profile > Products links disappear from admin bar links when on the homepage
- Fix – Added ABSPATH checks to all files
- Fix – Fixes a fatal error when $product->get_id() is called in Profile > Favorites Shops
- Fix – Mark favorite button working again on seller page