Custom Vehicle Selector visual improvements

Custom vehicle selector now affected by theme change. Cosnistent with other actrive elements

custom-example/res/Custom/Widgets/CustomVehicleButton.qml

@@ -47,7 +47,7 @@ Button {
 
     background: Rectangle {
         anchors.fill:               parent
-        color:                      button.checked ? qgcPal.window : qgcPal.button
+        color:                      button.checked ? qgcPal.buttonHighlight : qgcPal.button
         radius:                     ScreenTools.defaultFontPixelWidth * 0.5
     }
 

custom-example/res/MainToolbar/CustomMultiVehicleSelector.qml

@@ -9,8 +9,8 @@
  *   @author Gus Grubba <gus@auterion.com>
  */
 
-import QtQuick          2.11
-import QtQuick.Controls 1.4
+import QtQuick                              2.11
+import QtQuick.Controls                     1.4
 
 import QGroundControl                       1.0
 import QGroundControl.Controls              1.0