CS: backslashes must also be escaped in single quoted strings as per our CS
Added: Sort clause for sections
Added: DatePublished sort clause for Solr
Added: methods to enqueue operations to be run at transaction commit
Added: more aliasing
Added: Implementation of the MultipleStringField
Changed: commenting code that doesn't work yet

Object states does not seem to be implemented completely, commenting for
now.
Changed: adapted Solr fixtures against results received
Added: Signals and Slots for Solr
Added: ContentService integration tests to Solr