fixed a serious problem when substituing entities using the Reader, the

* parser.c xmlreader.c include/libxml/parser.h: fixed a serious
  problem when substituing entities using the Reader, the entities
  content might be freed and if rereferenced would crash
* Makefile.am test/* result/*: added a new test case and a new
  test operation for the reader with substitution of entities.
Daniel
diff --git a/result/dav8.rde b/result/dav8.rde
new file mode 100644
index 0000000..f14225e
--- /dev/null
+++ b/result/dav8.rde
@@ -0,0 +1,51 @@
+0 1 d:multistatus 0 0
+1 14 #text 0 1 
+  
+1 1 d:response 0 0
+2 14 #text 0 1 
+    
+2 1 d:href 0 0
+3 3 #text 0 1 http://www.foo.bar/othercontainer/resource1
+2 15 d:href 0 0
+2 14 #text 0 1 
+    
+2 1 d:href 0 0
+3 3 #text 0 1 http://www.foo.bar/othercontainer/resource2
+2 15 d:href 0 0
+2 14 #text 0 1 
+    
+2 1 d:href 0 0
+3 3 #text 0 1 http://www.foo.bar/othercontainer/
+2 15 d:href 0 0
+2 14 #text 0 1 
+    
+2 1 d:href 0 0
+3 3 #text 0 1 http://www.foo.bar/othercontainer/R2/D2
+2 15 d:href 0 0
+2 14 #text 0 1 
+    
+2 1 d:status 0 0
+3 3 #text 0 1 HTTP/1.1 201 Created
+2 15 d:status 0 0
+2 14 #text 0 1 
+  
+1 15 d:response 0 0
+1 14 #text 0 1 
+  
+1 1 d:response 0 0
+2 14 #text 0 1 
+    
+2 1 d:href 0 0
+3 3 #text 0 1 http://www.foo.bar/othercontainer/R2/
+2 15 d:href 0 0
+2 14 #text 0 1 
+    
+2 1 d:status 0 0
+3 3 #text 0 1 HTTP/1.1 412 Precondition Failed
+2 15 d:status 0 0
+2 14 #text 0 1 
+  
+1 15 d:response 0 0
+1 14 #text 0 1 
+
+0 15 d:multistatus 0 0