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_textlabel.h

@@ -0,0 +1,75 @@
+/* -*- 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_TEXT_LABEL_H
+#define QWT_PLOT_TEXT_LABEL_H 1
+
+#include "qwt_global.h"
+#include "qwt_plot_item.h"
+#include "qwt_text.h"
+
+/*!
+  \brief A plot item, which displays a text label
+
+  QwtPlotTextLabel displays a text label aligned to the plot canvas.
+
+  In opposite to QwtPlotMarker the position of the label is unrelated to
+  plot coordinates.
+
+  As drawing a text is an expensive operation the label is cached
+  in a pixmap to speed up replots.
+
+  \par Example
+    The following code shows how to add a title.
+    \code
+      QwtText title( "Plot Title" );
+      title.setRenderFlags( Qt::AlignHCenter | Qt::AlignTop );
+
+      QFont font;
+      font.setBold( true );
+      title.setFont( font );
+
+      QwtPlotTextLabel *titleItem = new QwtPlotTextLabel();
+      titleItem->setText( title );
+      titleItem->attach( plot );
+    \endcode
+  \endpar
+
+  \sa QwtPlotMarker
+*/
+
+class QWT_EXPORT QwtPlotTextLabel: public QwtPlotItem
+{
+public:
+    QwtPlotTextLabel();
+    virtual ~QwtPlotTextLabel();
+
+    virtual int rtti() const;
+
+    void setText( const QwtText & );
+    QwtText text() const;
+
+    void setMargin( int margin );
+    int margin() const;
+
+    virtual QRectF textRect( const QRectF &, const QSizeF & ) const;
+
+protected:
+    virtual void draw( QPainter *,
+        const QwtScaleMap &, const QwtScaleMap &,
+        const QRectF &) const;
+
+    void invalidateCache();
+
+private:
+    class PrivateData;
+    PrivateData *d_data;
+};
+
+#endif