Make the Buffer class non-copyable, otherwise LyX crashes when 'Impl * const d' is deleted while deleting a copy of the Buffer.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@39515 a592a061-630c-0410-9148-cb99ea01b6c8

src/Buffer.h

@@ -673,6 +673,9 @@ private:
 	///
 	void collectChildren(ListOfBuffers & children, bool grand_children) const;
 
+	/// noncopyable
+	Buffer(Buffer const &);
+	void operator=(Buffer const &);
 
 	/// Use the Pimpl idiom to hide the internals.
 	class Impl;