AvlGraph.hs: added prefixMappings function to AvlGraph.
AvlGraph.hs: added prefixMappings function to AvlGraph.

darcs-hash:20071106014625-db1bb-6977dee8dc196abebeccb1cae7d12f38a1a2fe96

jutaro/rdf4h,LeifW/rdf4h,ddssff/rdf4h,cordawyn/rdf4h