lodestar returns HTTP status 200 for resources that do not exist

[danizen]

For example:

http://www.ebi.ac.uk/rdf/services/biomodels/describe?uri=http%3A%2F%2Fidentifiers.org%2Fbiomodels.db%2FBIOMD0000000001%23_000003foobar

Simon, we have code that almost fixes this problem. The issue is how far to go to fix it.