renaming testCatalog as xmlcatalog, making it an installed app adding a

* Makefile.am xmlcatalog.c libxml.spec.in: renaming
  testCatalog as xmlcatalog, making it an installed app
  adding a shell, and preparing it to be a /etc/xml/catalog
  management tool, though not ready yet
* catalog.c include/libxml/catalog.h: adding support for
  XML Catalogs http://www.oasis-open.org/committees/entity/
  not finished, there is some interesting tradeoffs and a
  few open questions left.
Daniel
diff --git a/libxml.spec.in b/libxml.spec.in
index 56aadad..efef779 100644
--- a/libxml.spec.in
+++ b/libxml.spec.in
@@ -122,6 +122,7 @@
 
 %{prefix}/lib/lib*.so.*
 %{prefix}/bin/xmllint
+%{prefix}/bin/xmlcatalog
 
 %files devel
 %defattr(-, root, root)