parse server responses for errors wrapped in messages with a status code of 200

1. added logic to inspect server responses for error objects to make sure that we pass them to the client appropriately (and relevant tests)
2. fixed a few minor linting problems 
3. lessened the decimal precision used to test equivalence of results to ensure that anything within a meter is considered identical.  see [here](http://gis.stackexchange.com/questions/8650/how-to-measure-the-accuracy-of-latitude-and-longitude) for more info

the only thing that i think warrants an especially close look is https://github.com/jgravois/geoservices-js/blob/error-handling/lib/geocode.js#L183
i'm not exactly sure why my own linting picked up the previous syntax as an error.  the modification did not have an adverse affect on existing tests, but it may be bad practice for some reason unknown to me.