[gnome-shell] (28 commits) ...appDisplay: Append new icons at the first available page after first

[Florian Müllner <fmuellner src gnome org>]

Summary of changes:

  427b9ac... iconGrid: Add drop target API (*)
  8e24ac6... appDisplay: Ignore dragging over leeways (*)
  1e31caf... appDisplay: Introduce moveItem API (*)
  2bc8175... appDisplay: Accept dropping any kind of icon over it (*)
  1d86424... appDisplay: Factor out item addition and removal methods (*)
  fae2078... appDisplay: Move icons when hovering the grid (*)
  8a50a8e... appDisplay: Allow incomplete pages (*)
  8e23ff8... gschema: Introduce the 'app-picker-layout' key (*)
  e1ea1d2... appDisplay: Introduce PageManager (*)
  e3f3297... appDisplay: Save pages after dropping (*)
  18234ea... appDisplay: Use custom function to retrieve item page and p (*)
  40de201... appDisplay: Factor out draggable code into AppViewItem (*)
  d04d6e0... appDisplay: Check 'app-picker-layout' to make icons draggab (*)
  f4ce1cf... appDisplay: Make FolderIcon draggable (*)
  783dbe2... appDisplay: Don't resort folders when name changes (*)
  b64ce21... appDisplay: Create app folder where the drop happened (*)
  d1cbf6c... appDisplay: Allow overshooting any icon (*)
  701d110... appDisplay: Restore dragged item's position on drag cancel (*)
  578ae29... appDisplay: Add placeholder when moving from folder dialog (*)
  cceb747... appDisplay: Ensure icons always are at the correct position (*)
  60311aa... appDisplay: Fully hide icon when dragging (*)
  704e08d... appDisplay: Move DnD code to BaseAppView (*)
  16a18f2... appDisplay: Only handle DnD when mapped (*)
  7afab2c... appDisplay: Factor out folder loading code (*)
  f06c257... appDisplay: Allow reordering folders (*)
  730a68d... appDisplay: Increase folder dialog popdown timeout (*)
  d93b51e... appDisplay: Use a drag monitor to check for out-of-dialog d (*)
  bde9740... appDisplay: Append new icons at the first available page af (*)

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