This is for institutions who have procured larger per day transfer
limits; it looks like the only way to do this now is by IP or using this
token/secret mechanism.

- Resolves VUFIND-1029.

Rewrite of MultiBackend driver with separate functions for all ILS driver methods. Fix to checkCapability to work properly with drivers using __call() magic method and more data to supportsMethod() for better decision-making including the possibility to use supportsMethod also without _call(). Updated MultiBackend tests.

- Resolves VUFIND-1013.

Currently this module accepts 'checks to skip' but since this is pretty
specialized to callnumber searches (although potentially useful
elsewhere) I created a new config category called 'transforms to apply'

- Resolves VUFIND-852.

- Resolves VUFIND-852.

- Resolves VUFIND-78.

- Resolves VUFIND-993
- Includes upgrade warning
- Includes unit tests

- Some contributions by Joe Atzberger, Chris Hallberg and Demian Katz.
- Resolves VUFIND-636.

- Resolves VUFIND-423.