- Works around problems caused by changing record IDs on the Summon side, using the bookmark feature provided by the Summon API
- Includes mechanism for fallback record loading
- Includes mechanisms for deduplication after record ID change

- Makes room for large search objects and paging information. 

- Added support for fetching VuFind account in ILS login primarily by the patron ID that the ILS driver returns. This allows long-term consistency if other user details like barcodes change.
- Note that this new field is currently ONLY populated when ILS authentication is used; it is ignored under other circumstances.

- Adds new database table for correlating external sessions to internal ones
- Includes command-line tool for maintenance

- Includes upgrade script support.

* truncate metadata values according to column data type definition (avoid fatal error in strict database mode)
* extend varchar datatype to 255 chars for columns resource.title and resource.author (maximize allowable text)

Refactored search table handling so that existing searches are updated instead of deleting and creating new ones.
- Fixed duplicate search elimination to not consider extra url parameters such as page.
- Added a simple checksum to search table rows so that duplicate elimination does not have to go through potentially all searches in current sessions history.
- Added a database upgrade that adds checksums to saved search rows.

- Builds upon earlier work by mbeh-ub and others in PR #246.

- Introduce DEFAULT_SEARCH_BACKEND constant.
- Deprecate now-redundant getResourceSource() record driver method.
- Implement upgrade functionality to adjust database.
- Resolves VUFIND-1139.

- Resolves VUFIND-272 and VUFIND-296.

Thanks to Mark Triggs for initial research and Kyle McGrogan for implementation work.