- Extend the inplace zone parser to detect violations of the RFC 1035 section 5.2 requirement that a zonefile consist of exactly one class, enabled by default, and extend its error reporting to say what the wrong and expected classes were (and also use this contextual error support for other errors where applicable).
- Remove the default IN last class and allow the last class to be set if needed, as RFC 1035 doesn't define a default class.
