setup API is too loose

[ConnorRigby]

in ref to #17, #38 and by extension #40 i would like to start an official discussion of the setup api.

I don't personally want to support both string and atom keys for things. And this is only one part of this particular issue. I would like to parse and confirm them before passing further down to be messed up anywhere. I think the parse_settings function @Hermanverschooten introduced is on the right track, but instead of coxing things into a proper shape, we should enforce the proper shape. I think the public api should raise ArgumentError's when options are not inputted correctly.

[Hermanverschooten]

I agree with your sentiment. As far as the String to Atom goes, currently the underlying WpaSupplicant requires an Atom. I know there is a pull request there too, to allow strings to be used. My idea is we should implement our strategy concerning the config, and massage it to confirm with the called APIs. That will also allow us to enforce our contract, and make it more clear to the users.

[ConnorRigby]

in 0.3.x releases, we are now logging an incompatible type for ifnames such as here

Next major version update, we will be actually enforcing incompatible types.

[ConnorRigby]

as of 0.3.7, you will receive warnings on incompatible settings. later versions will officially deprecate old apis