Andrew: Added @throws declarations for explicit (but unchecked) IllegalArgumentException throws.
Andrew: Revised class comments for new Command, Command Extension, Response and Response Extension classes. Still being revised.
Andrew: Attempting to trigger another push.
Andrew: Revised Javadoc issues.
Added clause referring to XPath parsing for all Response extensions, since the clause is valid for all of them. Added simple doc for Variants v1.0.
Andrew: Re-adding misplaced Package Info documentation and other documentation tweaks.
Merge branch 'master' of https://github.com/AusRegistry/ari-toolkit