[redland-dev] raptor turtle serializer scalability patch

[Dave Beckett]

Right, it's a bit later and I still haven't figured out how to make 
rdfdiff work - that's a harder problem.  So instead of that, I'm going
to adjust the test framework to make it not use rdfdiff for the tests
it tails, and apply this turtle serializer patch.  It's not the best
solution but it does result in a working test suite and get this patch
out.

I've just committed this as SVN r15690 on the raptor1 branch, since it's a 
bug fix.

Dave