Enable Context Help (Shift+F1) using "QT's - What's This"

... adds "What's this" to (hopefully) most of the widgets (please report
on missing ones)
... defines draft "Whats' this" texts including a
context specific WikiLink

.. Help Key for all platforms is <Shift>+<F1> + in some widgets
"RightMouse - Click"

... Tested on Win and Mac (On Mac QtMacButton seems not supporting
"What's this") - so here <Shift>+<F1> has no result.

... ToDo: Create final texts and links based on the to be updated 3.11
Wiki

src/GoogleMapControl.cpp

@@ -30,6 +30,7 @@
 #include "Colors.h"
 #include "Units.h"
 #include "TimeUtils.h"
+#include "HelpWhatsThis.h"
 
 // overlay helper
 #include "TabView.h"
@@ -41,6 +42,7 @@ GoogleMapControl::GoogleMapControl(Context *context) : GcChartWindow(context), c
                                                        range(-1), current(NULL), firstShow(true)
 {
     setControls(NULL);
+
     setContentsMargins(0,0,0,0);
     layout = new QVBoxLayout();
     layout->setSpacing(0);
@@ -55,6 +57,9 @@ GoogleMapControl::GoogleMapControl(Context *context) : GcChartWindow(context), c
     view->setAcceptDrops(false);
     layout->addWidget(view);
 
+    HelpWhatsThis *help = new HelpWhatsThis(view);
+    view->setWhatsThis(help->getWhatsThisText(HelpWhatsThis::ChartRides_Map));
+
     webBridge = new WebBridge(context, this);
 
     // put a helper on the screen for mouse over intervals...