Added charset=UTF-8 in Content-Type and Encoded the update paramenter to UTF-8.
Skip SPARQLStore test if SPARQLWrapper is not installed

Trying to package RDFLib 4.1.0 on Fedora, I ran into a blocker with this test.
SPARQLWrapper is not yet packaged for Fedora, and unlike other tests which are
skipped if SPARQLWrapper is not installed, this one throws a fatal error. So
let's skip it like the others.

Signed-off-by: Dan Scott <dan@coffeecode.net>
Merge pull request #359 from dbs/skip_sparqlstore

Skip SPARQLWrapper test if SPARQLWrapper is not installed
correct unicode escape regex, fixes #352
SPARQLStore, set update_endpoint, even if None
Merged https://github.com/KMax/rdflib

Fixes #356
Raise exception for repeat node-object in rdf/xml parser. Test + fixes #363
raise the SkipTest exception, fixes #364
code cleanup (move imports and SkipTest exceptions to top)
Merge remote-tracking branch 'upstream'