added an encoding "special comment" to avoid warning message in python2.3

* python/drv_libxml.py: added an encoding "special comment" to avoid
  warning message in python2.3 (bug 146889)
* Makefile.am, python/Makefile.am, python/tests/Makefile.am: small
  change to make "make tests" a little quieter (MAKEFLAGS+=--silent)
* xpath.c: enhanced to take advantage of current libxslt handling
  of tmpRVT.  Fixes bug 145547.
diff --git a/python/tests/Makefile.am b/python/tests/Makefile.am
index 259a1bf..2788c0c 100644
--- a/python/tests/Makefile.am
+++ b/python/tests/Makefile.am
@@ -46,7 +46,7 @@
 
 if WITH_PYTHON
 tests: $(PYTESTS)
-	echo "## running Python regression tests"
+	@echo "## running Python regression tests"
 	-@(PYTHONPATH="..:../.libs:$(srcdir)/..:$$PYTHONPATH" ; \
 	   export PYTHONPATH; \
 	   for test in $(PYTESTS) ; \