Add new FactComboBox

src/FactSystem/FactControls/FactComboBox.qml

+import QtQuick 2.2
+import QtQuick.Controls 1.2
+import QtQuick.Controls.Styles 1.2
+
+import QGroundControl.FactSystem 1.0
+import QGroundControl.Palette 1.0
+import QGroundControl.Controls 1.0
+
+QGCComboBox {
+    property Fact fact: Fact { value: 0 }
+    currentIndex: fact.value
+    onActivated: fact.value = index
+}

src/FactSystem/FactControls/qmldir

 Module QGroundControl.FactControls
+
 FactLabel 1.0 FactLabel.qml
 FactTextField 1.0 FactTextField.qml
-FactCheckBox 1.0 FactCheckBox.qml
\ No newline at end of file
+FactCheckBox 1.0 FactCheckBox.qml
+FactComboBox 1.0 FactComboBox.qml
\ No newline at end of file