Added clarification about CFG_CALL_BIBFORMAT option being used only in the old (PHP) formatting engine.  Its value does not matter for the new (Python) formatting engine.
Added clarification about CFG_CALL_BIBFORMAT option being used only in
the old (PHP) formatting engine.  Its value does not matter for the
new (Python) formatting engine.

inveniosoftware/invenio,tiborsimko/invenio,inveniosoftware/invenio,tiborsimko/invenio