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_interval_symbol.h

@@ -0,0 +1,86 @@
+/* -*- 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_INTERVAL_SYMBOL_H
+#define QWT_INTERVAL_SYMBOL_H
+
+#include "qwt_global.h"
+#include <qpen.h>
+#include <qsize.h>
+
+class QPainter;
+class QRect;
+class QPointF;
+
+/*!
+  \brief A drawing primitive for displaying an interval like an error bar
+
+  \sa QwtPlotIntervalCurve
+*/
+class QWT_EXPORT QwtIntervalSymbol
+{
+public:
+    //! Symbol style
+    enum Style
+    {
+        //! No Style. The symbol cannot be drawn.
+        NoSymbol = -1,
+
+        /*!
+          The symbol displays a line with caps at the beginning/end.
+          The size of the caps depends on the symbol width().
+         */
+        Bar,
+
+        /*!
+          The symbol displays a plain rectangle using pen() and brush().
+          The size of the rectangle depends on the translated interval and
+          the width(),
+         */
+        Box,
+
+        /*!
+          Styles >= UserSymbol are reserved for derived
+          classes of QwtIntervalSymbol that overload draw() with
+          additional application specific symbol types.
+         */
+        UserSymbol = 1000
+    };
+
+public:
+    QwtIntervalSymbol( Style = NoSymbol );
+    QwtIntervalSymbol( const QwtIntervalSymbol & );
+    virtual ~QwtIntervalSymbol();
+
+    QwtIntervalSymbol &operator=( const QwtIntervalSymbol & );
+    bool operator==( const QwtIntervalSymbol & ) const;
+    bool operator!=( const QwtIntervalSymbol & ) const;
+
+    void setWidth( int );
+    int width() const;
+
+    void setBrush( const QBrush & );
+    const QBrush& brush() const;
+
+    void setPen( const QColor &, qreal width = 0.0, Qt::PenStyle = Qt::SolidLine );
+    void setPen( const QPen & );
+    const QPen& pen() const;
+
+    void setStyle( Style );
+    Style style() const;
+
+    virtual void draw( QPainter *, Qt::Orientation,
+        const QPointF& from, const QPointF& to ) const;
+
+private:
+    class PrivateData;
+    PrivateData* d_data;
+};
+
+#endif