Add the 'bayesian matching' preference that was hidden in the code.

[David Hampton]

Log Message:
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Add the 'bayesian matching' preference that was hidden in the code.

Tags:
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gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/import-export:
        import-backend.c
        import-settings.c
    gnucash/src/import-export/schemas:
        apps_gnucash_import_generic_matcher.schemas