message: Use constructor init list for control text in MajorEventAnnouncement
diff: using namespace NAS2D;
  -MajorEventAnnouncement::MajorEventAnnouncement()
  +MajorEventAnnouncement::MajorEventAnnouncement() :
  + btnClose{"Okay"}
  {
  init();
  }
  @@ -27,7 +28,6 @@ void MajorEventAnnouncement::init()
  size(522, 340);
  add(&btnClose, 5, 310);
  - btnClose.text("Okay");
  btnClose.size(512, 25);
  btnClose.click().connect(this, &MajorEventAnnouncement::btnCloseClicked);
  