[latexila] (8 commits) ...app: implement the app.quit action

[Sébastien Wilmet <swilmet src gnome org>]

Summary of changes:

  a734bb6... Add an app menu (*)
  b74768f... Set GtkWindow:application property before showing the GtkWi (*)
  8323e93... app: implement app.preferences action (*)
  1b7672c... app: implement the app.manage-build-tools action (*)
  6912702... app: implement the app.help action (*)
  30c3bcb... app: implement the app.fundraiser action (*)
  f5ae645... app: implement the app.about action (*)
  9e05cf9... app: implement the app.quit action

(*) This commit already existed in another branch; no separate mail sent