#1183 Abbreviate/unabbreviate journal names fails in biblatex mode

[Joseph Wright]

The abbreviate/unabbreviate tool for journal names seems to be hard coded for the journal field. As such, it does nothing in biblatex mode (which uses journaltitle), but will abbreviate a journal field if added manually. Presumably both fields should be altered or at least the code should pick up the change of standard field name.