Detect browser language if it's available

Addresses #37 by:

- checking if user has set language using cookie; otherwise it will read language from window.navigator
- checking if language matches a language available for the map
- finding a close match for the language (for example, languages en-US and en-GB should use en if there is not a more specific language available)
- uses $.each to set up language UI
- continues to default to English