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_plot_legenditem.h

@@ -0,0 +1,136 @@
+/* -*- 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_PLOT_LEGEND_ITEM_H
+#define QWT_PLOT_LEGEND_ITEM_H
+
+#include "qwt_global.h"
+#include "qwt_plot_item.h"
+#include "qwt_legend_data.h"
+
+class QFont;
+
+/*!
+  \brief A class which draws a legend inside the plot canvas
+
+  QwtPlotLegendItem can be used to draw a inside the plot canvas.
+  It can be used together with a QwtLegend or instead of it
+  to have more space for the plot canvas.
+
+  In opposite to QwtLegend the legend item is not interactive.
+  To identify mouse clicks on a legend item an event filter
+  needs to be installed catching mouse events ob the plot canvas.
+  The geometries of the legend items are available using
+  legendGeometries().
+
+  The legend item is aligned to plot canvas according to
+  its alignment() flags. It might have a background for the
+  complete legend ( usually semi transparent ) or for
+  each legend item.
+
+  \note An external QwtLegend with a transparent background
+        on top the plot canvas might be another option
+        with a similar effect.
+*/
+
+class QWT_EXPORT QwtPlotLegendItem: public QwtPlotItem
+{
+public:
+    /*!
+      \brief Background mode
+
+      Depending on the mode the complete legend or each item
+      might have an background.
+
+      The default setting is LegendBackground.
+
+       \sa setBackgroundMode(), setBackgroundBrush(), drawBackground()
+     */
+    enum BackgroundMode
+    {
+        //! The legend has a background
+        LegendBackground,
+
+        //! Each item has a background
+        ItemBackground
+    };
+
+    explicit QwtPlotLegendItem();
+    virtual ~QwtPlotLegendItem();
+
+    virtual int rtti() const;
+
+    void setAlignment( Qt::Alignment );
+    Qt::Alignment alignment() const;
+
+    void setMaxColumns( uint );
+    uint maxColumns() const;
+
+    void setMargin( int );
+    int margin() const;
+
+    void setSpacing( int );
+    int spacing() const;
+
+    void setItemMargin( int );
+    int itemMargin() const;
+
+    void setItemSpacing( int );
+    int itemSpacing() const;
+
+    void setFont( const QFont& );
+    QFont font() const;
+
+    void setBorderDistance( int );
+    int borderDistance() const;
+
+    void setBorderRadius( double );
+    double borderRadius() const;
+
+    void setBorderPen( const QPen & );
+    QPen borderPen() const;
+
+    void setBackgroundBrush( const QBrush & );
+    QBrush backgroundBrush() const;
+
+    void setBackgroundMode( BackgroundMode );
+    BackgroundMode backgroundMode() const;
+
+    void setTextPen( const QPen & );
+    QPen textPen() const;
+
+    virtual void draw( QPainter *,
+        const QwtScaleMap &xMap, const QwtScaleMap &yMap,
+        const QRectF &canvasRect ) const;
+
+    void clearLegend();
+
+    virtual void updateLegend( const QwtPlotItem *,
+        const QList<QwtLegendData> & );
+
+    virtual QRect geometry( const QRectF &canvasRect ) const;
+
+    virtual QSize minimumSize( const QwtLegendData & ) const;
+    virtual int heightForWidth( const QwtLegendData &, int width ) const;
+
+    QList< const QwtPlotItem * > plotItems() const;
+    QList< QRect > legendGeometries( const QwtPlotItem * ) const;
+
+protected:
+    virtual void drawLegendData( QPainter *painter,
+        const QwtPlotItem *, const QwtLegendData &, const QRectF & ) const;
+
+    virtual void drawBackground( QPainter *, const QRectF &rect ) const;
+
+private:
+    class PrivateData;
+    PrivateData *d_data;
+};
+
+#endif