[Linux] CA state parsing, robuster handshake, persistent window (#94)

* [Linux] Don't quit app when closing window

* Add magic pairing functionality

* BLE: Allow selecting text

* Parse CA state from airpods

* Add ability to disable cross-device

* More robust handshake/notification request

linux/Main.qml

@@ -2,11 +2,16 @@ import QtQuick 2.15
 import QtQuick.Controls 2.15
 
 ApplicationWindow {
+    id: mainWindow
     visible: true
     width: 400
     height: 300
     title: "AirPods Settings"
 
+    onClosing: function(event) {
+        mainWindow.visible = false
+    }
+
     Column {
         anchors.left: parent.left
         anchors.right: parent.right