Merge lp:~costales/unav/0.68-centerpos-btn-landscape into lp:unav

[costales]

Center position btn is not changing the opacity in landscape

=== modified file 'qml/Main.qml'
--- qml/Main.qml	2017-03-21 22:06:37 +0000
+++ qml/Main.qml	2017-04-01 21:17:12 +0000
@@ -561,8 +561,10 @@
                         }
 
                         ActionIcon {
+                            id: centerPosBtn
                             icon.name: mainPageStack.center_onpos ? "media-optical-symbolic" : "gps"
                             enabled: navigationPage.buttonsEnabled && mainPageStack.center_onpos !== 2
+                            opacity: centerPosBtn.enabled ? 1.0 : 0.2 // enabled property is not changing the opacity of the icon
                             onClicked: {
                                 if (mainPageStack.center_onpos === 0) {
                                     notificationBar.text =  i18n.tr("Searching your position… This could take a while");