The first unit test forces the File API to be more picky as any sane
core API should be. The second one illustrates the buggy behaviour of
the current implementation of delete_reference(). They both fail at the
moment, of course...
This patch unifies the way how records in {files_reference} get created.
Previously, each reference file (i.e. a file with referencefileid set)
created its own record in {files_reference}. This patch makes sure that
existing record is reused if possible.
Bye bye 1:1 relationships, you suck!
1. Added tracker issue number in comment
2. Fixed stored_file::delete_reference()
3. repository::send_file() will throw exception if not implemented by subclass
4. Fixed renaming unit test, added one unit test for deleting original file
5. Fixed copyright statement for googledoc and picasa repository plugin
6. Implemented stored_file::set_filesize()
