Merge branch 'release/2.27.1'

Jenkinsfile

oaipmh-core/.gitignore

oaipmh-core/pom.xml

...c/main/java/info/textgrid/middleware/DARIAHConstants.java

...main/java/info/textgrid/middleware/DublinCoreBuilder.java

.../java/info/textgrid/middleware/DublinCoreFieldLoader.java

.../src/main/java/info/textgrid/middleware/ErrorHandler.java

.../textgrid/middleware/IdentifierListDelivererAbstract.java

...a/info/textgrid/middleware/IdentifierListDelivererDC.java

...nfo/textgrid/middleware/IdentifierListDelivererIDIOM.java

...textgrid/middleware/IdentifierListDelivererInterface.java

...info/textgrid/middleware/MetadataFormatListDeliverer.java

...re/src/main/java/info/textgrid/middleware/OAIPMHImpl.java

.../main/java/info/textgrid/middleware/OAIPMHUtillities.java

.../src/main/java/info/textgrid/middleware/OAI_ESClient.java

.../src/main/java/info/textgrid/middleware/OaiPmhClient.java

...c/main/java/info/textgrid/middleware/RecordDeliverer.java

...ava/info/textgrid/middleware/RecordDelivererAbstract.java

...main/java/info/textgrid/middleware/RecordDelivererDC.java

...n/java/info/textgrid/middleware/RecordDelivererIDIOM.java