Views Filters handlers for field_publisher_ref, field_publisher_assignee and field_assignee, allowing active values to be presented as a dropdown in a Views filter.
Use the new Views Filter handlers in the Data Requests view
Remove the instance-specific filter for field_publisher_assignee - reworking into a generic filter for any instance of this field
Rework the field_assignee filter into a generic assignee filter, which can deal with any instance of the assginee field
Don't populate with default-values - either correct data or nothing
Remove dgu_views_filters module - field_publisher_ref exposed view filter is being handled by a patch to ckan_publisher_tree
Make method behaviour better match parent method
Changes backported from Pawel's fix to ckan_publisher_tree
Merge pull request #410 from djotto/fix_redmine_1618

Fix redmine 1618