TODO

Release 0.1: "must have"
========================
v take a deep breath and a long look at the GTK+ api, follow it as much as
  possible, ie change DockPaned.insert_item(item, ...) to
  DockPaned.insert_item(child, ...), etc

v fix DockPaned once and for all

v fix the DockGroup tab rendering bug
    > implies reviewing the _tabs/_visible_tabs system and it's interaction
      with tab ordering...
    > right moment to implement "tab order" property (alphabetical,
      opening order, last used, more?)

v implement the group-id system, can be used to configure:
    - auto remove empty dockgroups
    - can float
    - expand (so you can have a group-id=documents with expand=True and
      a group-id=tools with expand=False). This should control the expand
      child property of DockPaned
    - ???

v implement full signal set on DockGroup, DockPaned, ???:
    v item-added
    v item-removed
    x item-reordered --> maybe in DockLayout
    v item-selected

    > reemit by DockLayout so the end user only needs to concern himself with
      DockLayout and DockItem widgets (beside designing an initial layout)

v emit 'item-closed'/'item-removed' when closing a floating window

Release 0.2: "no rush"
======================
- use native gtk themeing to render all widgets, make the eclipse based "compact"
  rendering optional.

- use PlaceHolderWindow to consistently hightlight _all_ drop zones

- minimize DockGroup to toolbar

- autoshow/hide minimized DockGroups


Release x: "when we have time"
==============================
- the gdk_draw_* functions have been deprecated for GTK+3, migrate to cairo

- fix DnD on win32 for gtk+ > 2.16.6: depends on gdk-win32 csw/grabs work :(

- keyboard navigation

- translations

- handle RTL

- accessibility