Ran this through `./ios/docs/install_docs.sh` to double-check things.
* Less-specific initializers above more-specific per Apple convention.
* Shores up `accessToken` docs as property, not a method.
* Edited comments for consistency and/or to keep them out of the docs.
`Map` should be able to deal with having no access token or JSON even while it’s running. Most of `Map` accounts for this situation, but `reloadStyle()` incorrectly assumes that one or the other is set. This change corrects the assumption in `reloadStyle()`.
Also expose the access token and style name to clients as ordinary KVO-compliant properties. Actually, they’re not so ordinary because they’re inspectable!
Ref #1070, #1147
