Added mathmech

+ added files
* bug fix in mm_trj

mathmech/errorwindow.h

@@ -0,0 +1,23 @@
+#ifndef ERRORWINDOW_H
+#define ERRORWINDOW_H
+
+#include <QMainWindow>
+
+namespace Ui {
+  class ErrorWindow;
+}
+
+class ErrorWindow : public QMainWindow
+{
+  Q_OBJECT
+  
+public:
+  explicit ErrorWindow(QWidget *parent = 0);
+  ~ErrorWindow();
+  void set_message(QString language, int mess);
+  
+private:
+  Ui::ErrorWindow *ui;
+};
+
+#endif /* ERRORWINDOW_H */