result.coordinates not working for maxmind_local

Hello,

The symptom of my issue was that result.coordinates was always returning [0.0, 0.0] for the coordinates.

I proved my issue with a test. However, when I tried to fix it, I ran into issues with the data held within the results object being a mixture of strings and symbols.

It appears that the maxmind_local (and maxmind, but I have not tested it) stores its results hash with symbols instead of strings. That is fine for the most part because the Result::MaxmindLocal class refers to keys as symbols within. However, the Result::Base class provides some methods, like coordinates, but looks up from the results hash via string keys.

I have tried to change the internals of Result::MaxmindLocal to use strings, but at least in the tests, the data hash is actually keyed with symbols, and I am not sure where the symbols are coming, from, considering all other tests and implementations use strings. I also considered perhaps porting over with_indifferent_access and applying it to the data hash, but I feel like that might be too big of a chainsaw.

I'm willing to implement a fix, but am unsure which implementation would be most likely to be accepted.

Thanks