* libxslt/variables.c: fixed a problem with global var override
  being reported as an error.
* tests/docs/Makefile.am tests/docs/bug-61.xml
  tests/general/Makefile.am tests/general/bug-61.*: added a
  specific example in the regression tests
* configure.in tests/Makefile.am tests/reports/*: adding a test
  to make sure redefinition of global variables in the same stylesheet
  are still reported
Daniel