Querying for conflicts [API change]

* In an allDocs query you can now request extra information about document conflicts,
  or you can have _only_ docs in conflict returned. (See doc-comments in CBLQuery.h.)
* This is especially powerful if you set up a CBLLiveQuery with it — you’ll get immediate
  notifications of conflicts.
* The same options are available in the REST API as ?include_conflicts=true and
  ?only_conflicts=true parameters to _all_docs.
* New method -{CBLNewRevision saveAllowingConflict:] allows you to save over a
  non-default revision, to resolve or create a conflict (similar to the new_edits=false mode
  in CouchDB.)
* CBLQuery.includeDeleted property is now deprecated; use allDocsMode instead.
Avoid a Clang static analyzer warning