Add support for startonlogon in appimage

packages/AppImage/PyBitmessage.yml

@@ -14,6 +14,7 @@ ingredients:
     - python-setuptools
     - python-sip
     - python-six
+    - python-xdg
     - sni-qt
   exclude:
     - libdb5.3

src/plugins/desktop_xdg.py

@@ -11,6 +11,9 @@ class DesktopXDG(object):
         menu_entry = Menu.parse().getMenu('Office').getMenuEntry(
             'pybitmessage.desktop')
         self.desktop = menu_entry.DesktopEntry if menu_entry else None
+        appimage = os.getenv('APPIMAGE')
+        if appimage:
+            self.desktop.set('Exec', appimage)
 
     def adjust_startonlogon(self, autostart=False):
         """Configure autostart according to settings"""