Make cross-platform styles for mapbox data.

[Mokosha]

At first, we want to be able to divorce the data from the styles, so that we can apply the style to dynamic data (#8, #9) but ultimately we also want to not have to reimplement the styles a gajillion times for each different platform. Figure out a way to reuse the styles (perhaps we store them in a shared database in a JSON format that all platforms can download and then parse into something the mapbox API can consume).