added merlin-c14n-two.tar.gz tests for c14n/exc-c14n and slightly modified

* result/c14n/exc-without-comments/merlin-c14n-two-*
  result/c14n/without-comments/merlin-c14n-two-*
  test/c14n/exc-without-comments/merlin-c14n-two-*
  test/c14n/without-comments/merlin-c14n-two-*
  testC14N.c Makefile.am: added merlin-c14n-two.tar.gz tests for
c14n/exc-c14n and slightly modified test script to handle
these test cases
* c14n.c: fixed bugs for complicated nodes set (namespace
without node and others from merlin-c14n-two.tar.gz)
* include/libxml/xpathInternals.h win32/dsp/libxml2.def.src
win32/libxml2.def.src: "opened" xmlXPathNodeSetFreeNs() function
for xmlsec performance patch
* xpath.c: fixed self::node() for namespaces and attributes
8 files changed