Add 'const' on XMLDocument::DeepCopy. This make us copy const
XMLDocument being copied to another document.
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 8a3f857..5cdedbb 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -2054,7 +2054,7 @@
 }

 

 

-void XMLDocument::DeepCopy(XMLDocument* target)

+void XMLDocument::DeepCopy(XMLDocument* target) const

 {

 	TIXMLASSERT(target);

     if (target == this) {