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_data.h

@@ -0,0 +1,87 @@
+/* -*- 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_DATA_H
+#define QWT_LEGEND_DATA_H
+
+#include "qwt_global.h"
+#include "qwt_text.h"
+#include "qwt_graphic.h"
+#include <qvariant.h>
+#include <qpixmap.h>
+#include <qmap.h>
+
+/*!
+  \brief Attributes of an entry on a legend
+
+  QwtLegendData is an abstract container ( like QAbstractModel )
+  to exchange attributes, that are only known between to
+  the plot item and the legend.
+
+  By overloading QwtPlotItem::legendData() any other set of attributes
+  could be used, that can be handled by a modified ( or completely
+  different ) implementation of a legend.
+
+  \sa QwtLegend, QwtPlotLegendItem
+  \note The stockchart example implements a legend as a tree
+        with checkable items
+ */
+class QWT_EXPORT QwtLegendData
+{
+public:
+    //! Mode defining how a legend entry interacts
+    enum Mode
+    {
+        //! The legend item is not interactive, like a label
+        ReadOnly,
+
+        //! The legend item is clickable, like a push button
+        Clickable,
+
+        //! The legend item is checkable, like a checkable button
+        Checkable
+    };
+
+    //! Identifier how to interprete a QVariant
+    enum Role
+    {
+        // The value is a Mode
+        ModeRole,
+
+        // The value is a title
+        TitleRole,
+
+        // The value is an icon
+        IconRole,
+
+        // Values < UserRole are reserved for internal use
+        UserRole  = 32
+    };
+
+    QwtLegendData();
+    ~QwtLegendData();
+
+    void setValues( const QMap<int, QVariant> & );
+    const QMap<int, QVariant> &values() const;
+
+    void setValue( int role, const QVariant & );
+    QVariant value( int role ) const;
+
+    bool hasRole( int role ) const;
+    bool isValid() const;
+
+    QwtGraphic icon() const;
+    QwtText title() const;
+    Mode mode() const;
+
+private:
+    QMap<int, QVariant> d_map;
+};
+
+#endif