Fix identifier in schemas, see #16.

onlineResource{} => removed doi
additionalIdentifiers{} => changed name to identifier[]:
 -objects have identifier, type, authority{};
 -authority has title, date[], responsibleParty[], and onlineResource[]
resourceIdentifier[] => removed sections
assignedId[] => replaced with identifier[]
Fix handling of links (uri, url, urn), see #17
Update keyword citation schema(#17), change citationMain to citationFull.
Start updates of examples to 0.6.0
Update examples to 0.6.0

Add full_example2.json and test.
Changed assignedId to identifier.
Update tests.
Merge pull request #18 from adiwg/dev

Merge in Dev