setting defaults for zoom invert and zoom step for Werners fix of #894

- inverse is now default
- 0.2 is zoom step default
expecting lots of flaming :)

src/Gui/CADNavigationStyle.cpp

@@ -71,7 +71,7 @@ const char* CADNavigationStyle::mouseButtons(ViewerMode mode)
     case NavigationStyle::DRAGGING:
         return QT_TR_NOOP("Press left and middle mouse button");
     case NavigationStyle::ZOOMING:
-        return QT_TR_NOOP("Scroll middle mouse button");
+        return QT_TR_NOOP("Scroll middle mouse button or middle and cklicking left");
     default:
         return "No description";
     }