tweak comments. fix copy to self case.

tinyxml2.cpp

@@ -2052,7 +2052,9 @@ void XMLDocument::Clear()
 void XMLDocument::DeepCopy(XMLDocument* target)
 {
 	TIXMLASSERT(target);
-	TIXMLASSERT(target != this);
+    if (target == this) {
+        return; // technically success - a no-op.
+    }
 
 	target->Clear();
 	for (const XMLNode* node = this->FirstChild(); node; node = node->NextSibling()) {

tinyxml2.h

@@ -866,16 +866,17 @@ public:
     virtual XMLNode* ShallowClone( XMLDocument* document ) const = 0;
 
 	/**
-		Make a copy of this node and all of the children
-		of this node.
+		Make a copy of this node and all its children.
 
 		If the 'document' is null, then the nodes will
-		be allocated in the current document. If specified,
-		memory will e allocated is the specified document.
+		be allocated in the current document. If document 
+        is specified, the memory will be allocated is the 
+        specified XMLDocument.
 
 		NOTE: This is probably not the correct tool to 
 		copy a document, since XMLDocuments can have multiple
-		top level XMLNodes. You probably want XMLDocument::DeepCopy()
+		top level XMLNodes. You probably want to use
+        XMLDocument::DeepCopy()
 	*/
 	XMLNode* DeepClone( XMLDocument* document ) const;
 
@@ -1825,8 +1826,7 @@ public:
 		The target will be completely cleared before the copy.
 		If you want to copy a sub-tree, see XMLNode::DeepClone().
 
-		NOTE: that the 'target' must be non-null and not
-		the source document.
+		NOTE: that the 'target' must be non-null.
 	*/
 	void DeepCopy(XMLDocument* target);