- Only affected PostgreSQL databases.
- We needed to better standardize the way the search object data was normalized.

- Avoids checking for existing records when we know there shouldn't be any duplicates.
- Moves setting source identifier of records inside the collection class to make it faster.

- In addition to making code more flexible, implement full support for the Search2 backend.

- Use properties to allow subclass overrides.

- Useful for supporting additional search backends.

- Makes subclassing possible without cache collisions.

- Prerequisite for supporting multiple backends in hierarchies.

Also makes sure that status is not fetched multiple times for an item if same container was used twice.

- Translations courtesy of Dr. Pragya Pandey, Mr. Komal Patel, Dr. Md. Nurul Alam and Prof. Parhasarathi Mukhopadhyay.

Also remove obsolete xhprof support.

- Potentially useful for retrying after encountering problems.