#4 - Upgraded to Salespoint 6.0.0.

Upgraded to Salespoint 6.0.0-SNAPSHOT. Switched to new Salespoint Maven repository. Added Spring release repository before the salespoint one to make sure we don't necessarily kill the Salespoint repo with requests for artifacts it won't serve by definition.

Adapted refactorings (package and API changes in Salespoint). Moved away from separate types for different Disc types and rather use an enum property on Disc. Polished integration tests. Added integration tests for VideoCatalog.

Related ticket: #3.