Govspeak in world org api

Render description and services of a worldwide organisation via govspeak_to_html in the API.  Services can be blank and if so we don't push it through govspeak so you get an empty string (instead of not having the key).

Don't render the main_office at all, and thus don't have an offices[:main] key in the API if the worldwide organisation has no main_office.

I realise now that these two changes take different approaches to missing stuff, should we standardise?  Should this be something that the API docs standardise on?