Serializer: change return type; sort read before write

GUI/Model/XML/Serializer.cpp

@@ -32,16 +32,6 @@ constexpr auto Version("version");
 
 } // namespace
 
-bool Serializer::xmlReader() const
-{
-    return m_r;
-}
-
-bool Serializer::xmlWriter() const
-{
-    return m_w;
-}
-
 void Serializer::writeVersion(unsigned version) const
 {
     if (!m_w)

GUI/Model/XML/Serializer.h

@@ -40,8 +40,8 @@ public:
     {
     }
 
-    bool xmlReader() const; //!< Returns true if this is a reader.
-    bool xmlWriter() const; //!< Returns true if this is a writer.
+    QXmlStreamWriter* xmlWriter() { return m_w; } //!< Returns stream writer or nullptr.
+    QXmlStreamReader* xmlReader() { return m_r; } //!< Returns stream reader or nullptr.
 
     //! As writer, serializes the given version number. As reader, does nothing.
     void writeVersion(unsigned version) const;