o Remove conditional compilation depending on HAVE_LIPUNP - we
  always have it, otherwise this project wouldn't make sense.
o Choose some default port that is a bit easier to remember
  yet in the range that libupnp imposes.
o Provide libupnp server configuration ip/port limitations in --help
o Debugging helps if optimization is switched off.
o fix leak.
o Better naming of string representation of XML documents.
o xmldoc: don't allocate holder objects, but directly hand out
  internal IXML pointers. The owernship semantics resulted in unfixable
  leaks.