GCS-Added gradient to edit gadgets bar

ground/openpilotgcs/share/openpilotgcs/stylesheets/default_linux.qss

@@ -1 +1,2 @@
 MyListWidget {font-size: 11px;}
+Utils--StyledBar { background-color: qlineargradient(spread:pad, x1:0, y1:0, x2:0, y2:1, stop:0 rgba(0, 0, 0, 255), stop:1 rgba(200, 200, 200, 255));}

ground/openpilotgcs/src/libs/utils/styledbar.h

@@ -37,6 +37,7 @@ namespace Utils {
 
 class QTCREATOR_UTILS_EXPORT StyledBar : public QWidget
 {
+    Q_OBJECT
 public:
     StyledBar(QWidget *parent = 0);
     void setSingleRow(bool singleRow);

ground/openpilotgcs/src/plugins/coreplugin/connectionmanager.h

@@ -41,6 +41,7 @@
 #include <QtGui/QComboBox>
 
 #include "core_global.h"
+#include <QTimer>
 
 QT_BEGIN_NAMESPACE
 class QTabWidget;