Finally fixed bug #75813, processing or Result Value Tree converted into

* libxslt/pattern.c libxslt/transform.c libxslt/variables.c:
  Finally fixed bug #75813, processing or Result Value Tree
  converted into node-sets should be a bit more sensible now.
* tests/exslt/common/node-set.2.out: the associated fix in libxml2
  fixes this regression test, there is 4 nodes, not 3
* tests/docs/Makefile.am tests/docs/bug-111.*
  tests/general/Makefile.am tests/general/bug-111*: added an
  example in the regression tests for bug #75813
Daniel