bugfix: attr when iterating DirectoryDocumentStore

Assign documentStore attribute to resulting Documents when
iterating over DirectoryDocumentStore.
bugfix: avoid TypeError when ranking deleted Records
bugfix: handle deleted Records in SRU

Provide a Diagnostic in place of the recordData for deleted Records
bugfix: DeletedObject deletion time
bugfix: handle deleted Records in OAI-PMH
admin: bumped version numbers
docs: update README and CHANGES file
Merge branch 'hotfix/1.1.3'