Fix Notice in case of empty product attributes group name
Added invoices tab to customers details page
Merge remote-tracking branch 'shineisp/master'
Removed translations from CustomersController due to https://github.com/shinesoftware/shineisp/commit/0911dcb88b091f2d8d2c2d8ca30320d10758488e
Merge pull request #2 from guestisp/master

Added invoices tab to customers details page