Provider.json should always be downloaded from website
Right now, those providers that are not "custom" are bundled with a provider.json file stored in assets.
This should not be this way, because provider.json should then be updated regularly and that's not efficient, it's much better to download it directly from website when the user chooses a provider.
I'll create another issue to manage the case in which provider.json changes and the user has already selected the provider.
(from redmine: created on 2013-05-08, closed on 2013-05-08)