[balsa] (14 commits) Non-fast-forward update to branch popover

[Peter Bloomfield <peterb src gnome org>]

The branch 'popover' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  8aa5951... pref-manager: Use GtkPopover for "Add" options
  f0d5f78... vfs: Port to GMenu
  5fd7d20... libbalsa-vfs: New API to use with GMenu

Commits added to the branch:

  ad6c70b... Correct metadata_license tag name in AppStream data. (*)
  d75e05b... Merge branch 'appinfo' into 'master' (*)
  4db63c1... README: Use American English spelling of "license" (*)
  5084375... Updated Spanish translation (*)
  ea1e79b... mailbox: Do not always cache message info (*)
  77a1f2e... Update Brazilian Portuguese translation (*)
  1dfeaff... Update Polish translation (*)
  7bbfc01... mailbox: Guard against out-of-bounds access (*)
  6b8d818... mailbox: Make cache-message a class method (*)
  af7be21... Drop LibBalsaMailbox:is_directory (*)
  aab43d0... Merge branch 'drop-is-directory' into 'master' (*)
  86bdc33... pref-manager: Use GtkPopover for "Add" options
  e309707... vfs: Port to GMenu
  1942472... libbalsa-vfs: New API to use with GMenu

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