First commit of the new Relax-NG validation code, not generally useful

* Makefile.am configure.in relaxng.c include/libxml/relaxng.h:
  First commit of the new Relax-NG validation code, not generally
  useful yet.
* test/relaxng/* result/relaxng/*: current state of the regression
  tests
Daniel
diff --git a/test/relaxng/tutor4_1_1.xml b/test/relaxng/tutor4_1_1.xml
new file mode 100644
index 0000000..9b8616a
--- /dev/null
+++ b/test/relaxng/tutor4_1_1.xml
@@ -0,0 +1,4 @@
+<addressBook>
+  <card><name>John Smith</name><email>js@example.com"</email></card>
+  <card><name>John Smith2</name><email>js2@example.com"</email></card>
+</addressBook>