CS-4863: Added missing getters and setters
CS-4863: Added getter and setter
CS-4863: Removed unneeded properties and replaced them with calls to linked entities

- Replaced issueId and sectionId by issue and section entities. Methods for
  checking issueId and sectionId still available but refer to entities.
- Replace setters for issueId and sectionId by setters for issue and session
  entities. Renamed methods.
- Fixed some minor method naming issues and returning self for setters.
WOBS-2931: Added repository for issues

Within repository a method is available to get the latest published issue for a
publication.
CS-4863: Added 'findByRFC3066bis' method to language repository
CS-4863: Adds getter and setter for ID and changes toString method

Also adds getNameAndLanguage method, which is used by toString method.
CS-4863: Enforces psr standards
CS-4863: Fixes error in Doctrine mapping
Merge pull request #445 from m038/CS-4863

Cs 4863