* 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.