Repository.delete() should throw RecordNotFoundException

[bruno]

Repository.delete() should throw a RecordNotFoundException? instead of silently skipping a non-existent record.

[bruno]

(In [4216]) Json interface (#60): adding more resources and more functionality to the existing resources. Added an ExceptionMapper? to format the error responses. All resources (URIs + methods on them) should now be present, but many of them still completely untested.

Some changes/fixes to the repository code:

• Repository.delete(): throw RecordNotFoundException?, previously delete silently skipped a non-existing record. Fixes #101.
• Repository.create(): removed unused but declared throws of RecordNotFoundException?, this exception makes no sense for record creation.
• Repository.getRow: the test to check if a record exists did not make sense, now it checks for the presence of the record type column. Fixes #102.