Make DNS.records lazy, for initialization order.
NS: Added AAAA Doc resolver, delegating resolver
Fixed a typo in NameServer comments.
Updated NameServer docs to reflect reality.
'Flipped' MessageBuffer bytes, ftw
Fixed AAAA delegation in NameServer
Factored out the test `Doc` from NameServer
Merge pull request #3 from mesosphere/doc-resolver

NS: Added AAAA Doc resolver, delegating resolver
Comment out SRV records.

Support in the future is mentioned in #4.
Clean up signatures, add docs.

Seems more logical to put diffing in Diff as apply of the companion object.
WIP
WIP