EDIT

fixed possible NPE and handling of null values

reintegrated campanula drupal branch

test for #4423 (DescriptionElement media no longer visible)

test for #4423 (DescriptionElement media no longer visible)

fixing #4423 (DescriptionElement media no longer visible)

bibliography is per default turend off

further fine tuning of feature block settings

cdm_feature_block_element_tag_name() incorporates value set in feature_block_settings['element_tag'] and further fine tuning of feature block settings

fixing #1803 (PALMS. Common names entered with Editor not displaying well in the portal), the CommonName elements respect the feature block settings so that source references as content are shown in the portal

adapting existing tests and adding a new one to reproduce #4383 (references in bibliography need de-duplication)