Qt5 built in qwt (#570)

- qt4->qt5
- in built qt5 6.1.5 because rhel7 is not upto date with qt5, removed findqwt.cmake
- made a fix in qwt lib (qwt_plot_layout.h) to work with 5.15 and lower versions for qrect constr.
- qt5 forms fixed, qt4 many hard coding forms switched to forms including qtabwidget, scrolls etc, fonts moved to forms
 - docking option enabled by default, removed option to disable docking feature from "Mode"
- added qVersionResolve utility functions to handle compatibility before and after qt5.12
- qtplots (ian's code) takes in gain mode enable to set some settings within the class, with proper gain plot ticks
- ensure gain plots have no zooming of z axis in 2d and y axis in 1d
- removed placeholder text in qpalette in main window form as its not supportd until 5.12 (so using qt5.9 designer insted of qt5.15 to cope)
- tab order
Servers:
- fixed some error messages that were empty for fail in funcs (mostly minor as if this error, major issues)

libs/qwt-6.1.5/include/qwt_legend_label.h

@@ -0,0 +1,80 @@
+/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
+ * Qwt Widget Library
+ * Copyright (C) 1997   Josef Wilgen
+ * Copyright (C) 2002   Uwe Rathmann
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the Qwt License, Version 1.0
+ *****************************************************************************/
+
+#ifndef QWT_LEGEND_LABEL_H
+#define QWT_LEGEND_LABEL_H
+
+#include "qwt_global.h"
+#include "qwt_legend_data.h"
+#include "qwt_text.h"
+#include "qwt_text_label.h"
+#include <qpixmap.h>
+
+class QwtLegendData;
+
+/*!
+  \brief A widget representing something on a QwtLegend.
+*/
+class QWT_EXPORT QwtLegendLabel: public QwtTextLabel
+{
+    Q_OBJECT
+public:
+    explicit QwtLegendLabel( QWidget *parent = 0 );
+    virtual ~QwtLegendLabel();
+
+    void setData( const QwtLegendData & );
+    const QwtLegendData &data() const;
+
+    void setItemMode( QwtLegendData::Mode );
+    QwtLegendData::Mode itemMode() const;
+
+    void setSpacing( int spacing );
+    int spacing() const;
+
+    virtual void setText( const QwtText & );
+
+    void setIcon( const QPixmap & );
+    QPixmap icon() const;
+
+    virtual QSize sizeHint() const;
+
+    bool isChecked() const;
+
+public Q_SLOTS:
+    void setChecked( bool on );
+
+Q_SIGNALS:
+    //! Signal, when the legend item has been clicked
+    void clicked();
+
+    //! Signal, when the legend item has been pressed
+    void pressed();
+
+    //! Signal, when the legend item has been released
+    void released();
+
+    //! Signal, when the legend item has been toggled
+    void checked( bool );
+
+protected:
+    void setDown( bool );
+    bool isDown() const;
+
+    virtual void paintEvent( QPaintEvent * );
+    virtual void mousePressEvent( QMouseEvent * );
+    virtual void mouseReleaseEvent( QMouseEvent * );
+    virtual void keyPressEvent( QKeyEvent * );
+    virtual void keyReleaseEvent( QKeyEvent * );
+
+private:
+    class PrivateData;
+    PrivateData *d_data;
+};
+
+#endif