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)

slsDetectorGui/include/qDetectorMain.h

@@ -4,9 +4,6 @@
 #include "qDefs.h"
 #include "sls/Detector.h"
 #include "ui_form_detectormain.h"
-#include <QTabWidget>
-
-class QScrollArea;
 class QResizeEvent;
 
 namespace sls {
@@ -21,15 +18,6 @@ class qTabDebugging;
 class qTabDeveloper;
 class qTabMessages;
 
-/** To Over-ride the QTabWidget class to get the tabBar protected
- * methodTabWidget */
-class MyTabWidget : public QTabWidget {
-  public:
-    MyTabWidget(QWidget *parent = 0) { setParent(parent); }
-    /** Overridden protected method from QTabWidget */
-    QTabBar *tabBar() { return QTabWidget::tabBar(); }
-};
-
 class qDetectorMain : public QMainWindow, private Ui::DetectorMainObject {
     Q_OBJECT
 
@@ -75,8 +63,6 @@ class qDetectorMain : public QMainWindow, private Ui::DetectorMainObject {
     slsDetectorDefs::detectorType detType;
     std::unique_ptr<Detector> det;
     qDrawPlot *plot;
-    MyTabWidget *tabs;
-    QScrollArea *scroll[NumberOfTabs];
     qTabMeasurement *tabMeasurement;
     qTabDataOutput *tabDataOutput;
     qTabPlot *tabPlot;
@@ -85,9 +71,7 @@ class qDetectorMain : public QMainWindow, private Ui::DetectorMainObject {
     qTabDebugging *tabDebugging;
     qTabDeveloper *tabDeveloper;
     qTabMessages *tabMessages;
-    int isDeveloper;
-    int heightPlotWindow;
-    int heightCentralWidget;
+    int isDeveloper{false};
     QString zoomToolTip;
     QColor defaultTabColor;
 };