These changes correlate with moving the API from https://api.luminoso.com/v4
to https://analytics.luminoso.com/api/v4.
* Client changes
- Documentation updated with new URL.
- URL_BASE updated in the constants (with API_VERSION and API_HOST being
removed as unnecessary)
- The logic for getting the "root url" when setting up a client is now
different; it uses /api/v4 unless the given URL is using /v4 (in which
case it uses /v4 but issues a warning about the new URL).
* Upload script changes
- Removed --local as an option, which was only usable internally.
- Replaced --readers option, which was only useful for internal users, with
a more broadly useful --language option.