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_null_paintdevice.h

@@ -0,0 +1,126 @@
+/* -*- 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_NULL_PAINT_DEVICE_H
+#define QWT_NULL_PAINT_DEVICE_H 1
+
+#include "qwt_global.h"
+#include <qpaintdevice.h>
+#include <qpaintengine.h>
+
+/*!
+  \brief A null paint device doing nothing
+
+  Sometimes important layout/rendering geometries are not
+  available or changeable from the public Qt class interface.
+  ( f.e hidden in the style implementation ).
+
+  QwtNullPaintDevice can be used to manipulate or filter out
+  this information by analyzing the stream of paint primitives.
+
+  F.e. QwtNullPaintDevice is used by QwtPlotCanvas to identify
+  styled backgrounds with rounded corners.
+*/
+
+class QWT_EXPORT QwtNullPaintDevice: public QPaintDevice
+{
+public:
+    /*!
+      \brief Render mode
+
+      \sa setMode(), mode()
+     */
+    enum Mode
+    {
+        /*!
+           All vector graphic primitives are painted by
+           the corresponding draw methods
+         */
+        NormalMode,
+
+        /*!
+           Vector graphic primitives ( beside polygons ) are mapped to a QPainterPath
+           and are painted by drawPath. In PathMode mode
+           only a few draw methods are called:
+
+           - drawPath()
+           - drawPixmap()
+           - drawImage()
+           - drawPolygon()
+         */
+        PolygonPathMode,
+
+        /*!
+           Vector graphic primitives are mapped to a QPainterPath
+           and are painted by drawPath. In PathMode mode
+           only a few draw methods are called:
+
+           - drawPath()
+           - drawPixmap()
+           - drawImage()
+         */
+        PathMode
+    };
+
+    QwtNullPaintDevice();
+    virtual ~QwtNullPaintDevice();
+
+    void setMode( Mode );
+    Mode mode() const;
+
+    virtual QPaintEngine *paintEngine() const;
+
+    virtual int metric( PaintDeviceMetric ) const;
+
+    virtual void drawRects(const QRect *, int );
+    virtual void drawRects(const QRectF *, int );
+
+    virtual void drawLines(const QLine *, int );
+    virtual void drawLines(const QLineF *, int );
+
+    virtual void drawEllipse(const QRectF &);
+    virtual void drawEllipse(const QRect &);
+
+    virtual void drawPath(const QPainterPath &);
+
+    virtual void drawPoints(const QPointF *, int );
+    virtual void drawPoints(const QPoint *, int );
+
+    virtual void drawPolygon(
+        const QPointF *, int , QPaintEngine::PolygonDrawMode );
+
+    virtual void drawPolygon(
+        const QPoint *, int , QPaintEngine::PolygonDrawMode );
+
+    virtual void drawPixmap(const QRectF &,
+        const QPixmap &, const QRectF &);
+
+    virtual void drawTextItem(const QPointF &, const QTextItem &);
+
+    virtual void drawTiledPixmap(const QRectF &,
+        const QPixmap &, const QPointF & );
+
+    virtual void drawImage(const QRectF &,
+        const QImage &, const QRectF &, Qt::ImageConversionFlags );
+
+    virtual void updateState( const QPaintEngineState & );
+
+protected:
+    //! \return Size needed to implement metric()
+    virtual QSize sizeMetrics() const = 0;
+
+private:
+    class PaintEngine;
+    PaintEngine *d_engine;
+
+    class PrivateData;
+    PrivateData *d_data;
+};
+
+#endif