Twiddled the loading of local models into memory datasets
so that the same internal ordering is used for the model as it was in the plain-model
version of the source. This avoids certain fragile test failures.
Added load of named graphs./
Tests passing after making the sample triples differ by subject as well as object.
Something odd about DESCRIBE on datasets/with GRAPH. One other test now failing.
Tuned the describe-query test -- it's fragile with respect to layout because it
is a textual comparison of SPARQL queries. We might want to at least turn them into Query objects and
test thsoe for equality.