[gitg] (26 commits) ...Do not pretend to support deleting remotes

[Jesse van den Kieboom <jessevdk src gnome org>]

Summary of changes:

  f0f119b... Added initial action interfaces in GitgExt (*)
  7cfa451... Added ref delete/rename action stubs (*)
  d0aa769... Implement history navigation as ListBox (*)
  799d90f... Rename GitgExt.RefAction to GitgExt.Action (*)
  0974aac... Add action interface implementation (*)
  3818eac... Implement GitgExt.Action interface (*)
  588d016... Improve selection and implemented editing (*)
  a42b958... Remove obsolete style (*)
  ad93f2c... Generalize info bar to user query (*)
  f2424d4... Added GitgExtUserQuery (*)
  0e2a96a... Implemented animations for refs list (*)
  456da85... Add clearing repository refs cache (*)
  3750ed9... Cleanly separate ref actions using interfaces (*)
  4b5bacc... Fix install targets (*)
  94c65b1... Set infobar action area to vertical orientation (*)
  669701f... Clear ref cache in action interface (*)
  0f9f252... Implemented delete action for tags and branches (*)
  5446366... Fix event cast (*)
  619a8bc... Add reflog messages (*)
  5c678a2... Remove use of deprecated properties (*)
  9616f91... Improve restore refs list selection (*)
  698bffc... Only select first ref unless multiselect (*)
  1ef395d... Scroll selection into view (*)
  d7a5c0e... Separate walker includes and selection (*)
  446bfa8... Select ref rows on button press (*)
  89adb46... Do not pretend to support deleting remotes (*)

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