Core pr 5

Minor bug fixes.
I think the dependency chain is a bit peculiar here.

We have a general setting `ding_user_fee_sms` to set that text messages incur a fee but the general module has no knowledge of whether the provider supports a cell phone  number for the user so that module does nothing but expose the admin form. We have to place the code for adding the message in the provider code.

Going forward perhaps it would be clearer to put duplicate such things in the providers if we cannot come up with a better solution.