Added multi language support, add &lang=en or &lang=nl to the url.
Example:
http://localhost:5000/?theme=web&lang=en&token=
If you want to add another language, copy any of the files here https://github.com/daneedk/homey.ink/tree/master/app/locales to start with. translate the texts and save it as [countrycode].json
When &lang= is omitted or invalid English will be used.
