sendMessage via signal plot from file to window,

add severity to messages (black, yellow, red),
add about text,
removed unused texture from resource

QtMeshViewer/Header/MshFile.h

@@ -20,7 +20,7 @@ enum ModelTyp {
 class MshFile : public FileInterface
 {
 public:
-	explicit MshFile(const char* path);
+	explicit MshFile(const char* path, QObject *parent = Q_NULLPTR);
 	virtual ~MshFile();
 
 private: