Taxes in database

Can now specify tax information in the database, therefore allow to change them dynamically. 
Will have to bake tax information in bill #18


<!---
@huboard:{"order":19.0,"milestone_order":19,"custom_state":"ready"}
-->

updated to 
```
    taxInfos: React.PropTypes.arrayOf(React.PropTypes.shape({
      localizeKey: React.PropTypes.string.isRequired,
      rate: React.PropTypes.number.isRequired
    })).isRequired
```