SemanticDbl: fixed problem with blank node ID
SemanticDbl: fixed problem with blank node ID

stored got confused about _:foobar and foobar, which means IDs where given
with _: and without. Now subject and object strings will be reduced by _:,
if at the beginning, because stored saves blank ids without _: internally.

furthermore getNodeValue returnes extended URI for named nodes.

k00ni/knorke