Upgrade rdf-turtle to 1.1.8.
Upgrade rdf-turtle to 1.1.8.

This version of the Turtle parser uses a hand-written parser that is
about 3x faster than the previous version. It also addresses the issue
with long literals. The monkey patch for that issue is reverted in
c0c44482; the regression test added by 0f9a1b722 remains.

dpla/KriKri,dpla/KriKri,dpla/KriKri,dpla/KriKri