web: fix Link header detection and slice<>
web: fix Link header detection and slice<>

nicola/rdflib.js,timbl/rdflib.js,ariutta/rdflib.js,timbl/rdflib.js,nicola/rdflib.js,ariutta/rdflib.js,ariutta/rdflib.js,timbl/rdflib.js,redaktor/rdflib.js,redaktor/rdflib.js