Add a boolean argument to prevent resolving CNAMEs

In some situations when querying for answers for a given domain, it may not
be desireable to resolve the domain to a CNAME if one exists. This is indeed
the requirement for dynamic updates, as an rrtype is always explicit.
Ensure there is no leading slash from nameToKey
Fixed type error
Added helper methods for domain/rrset validation checks
Added more useful debug logging