Fixed cppcheck warnings
diff --git a/tinyxml2.h b/tinyxml2.h
index 13629f4..1ad2f6f 100644
--- a/tinyxml2.h
+++ b/tinyxml2.h
@@ -587,7 +587,7 @@
 	XMLNode( XMLDocument* );

 	virtual ~XMLNode();

 	XMLNode( const XMLNode& );	// not supported

-	void operator=( const XMLNode& );	// not supported

+	XMLNode& operator=( const XMLNode& );	// not supported

 	

 	XMLDocument*	document;

 	XMLNode*		parent;

@@ -641,7 +641,7 @@
 	XMLText( XMLDocument* doc )	: XMLNode( doc ), isCData( false )	{}

 	virtual ~XMLText()												{}

 	XMLText( const XMLText& );	// not supported

-	void operator=( const XMLText& );	// not supported

+	XMLText& operator=( const XMLText& );	// not supported

 

 private:

 	bool isCData;

@@ -666,7 +666,7 @@
 	XMLComment( XMLDocument* doc );

 	virtual ~XMLComment();

 	XMLComment( const XMLComment& );	// not supported

-	void operator=( const XMLComment& );	// not supported

+	XMLComment& operator=( const XMLComment& );	// not supported

 

 private:

 };

@@ -700,7 +700,7 @@
 	XMLDeclaration( XMLDocument* doc );

 	virtual ~XMLDeclaration();

 	XMLDeclaration( const XMLDeclaration& );	// not supported

-	void operator=( const XMLDeclaration& );	// not supported

+	XMLDeclaration& operator=( const XMLDeclaration& );	// not supported

 };

 

 

@@ -728,7 +728,7 @@
 	XMLUnknown( XMLDocument* doc );

 	virtual ~XMLUnknown();

 	XMLUnknown( const XMLUnknown& );	// not supported

-	void operator=( const XMLUnknown& );	// not supported

+	XMLUnknown& operator=( const XMLUnknown& );	// not supported

 };

 

 

@@ -1265,7 +1265,7 @@
 	/// Copy constructor

 	XMLHandle( const XMLHandle& ref )										{ node = ref.node; }

 	/// Assignment

-	XMLHandle operator=( const XMLHandle& ref )								{ node = ref.node; return *this; }

+	XMLHandle& operator=( const XMLHandle& ref )							{ node = ref.node; return *this; }

 

 	/// Get the first child of this handle.

 	XMLHandle FirstChild() 													{ return XMLHandle( node ? node->FirstChild() : 0 ); }

@@ -1311,7 +1311,7 @@
 	XMLConstHandle( const XMLNode& _node )											{ node = &_node; }

 	XMLConstHandle( const XMLConstHandle& ref )										{ node = ref.node; }

 

-	XMLConstHandle operator=( const XMLConstHandle& ref )							{ node = ref.node; return *this; }

+	XMLConstHandle& operator=( const XMLConstHandle& ref )							{ node = ref.node; return *this; }

 

 	const XMLConstHandle FirstChild() const											{ return XMLConstHandle( node ? node->FirstChild() : 0 ); }

 	const XMLConstHandle FirstChildElement( const char* value=0 ) const				{ return XMLConstHandle( node ? node->FirstChildElement( value ) : 0 ); }