spatial stuff detail

[Dave Camp <dave ximian com>]

I just committed the start of the spatial UI stuff to the
nautilus-spatial-playground branch.  It'd be nice if people could
pound on it for a little bit.

What has changed from a UI perspective:

* Object windows are created by default from the desktop.  Navigation
  windows can be opened from the menus.  Right now all that is
  implemented is Open With -> Navigation Window, but a "New Navigation
  Window" entry in the desktop context menu could pretty easily be
  created.

* Object windows are one-window-per-location.  They do not have the
  following UI:
  - Search UI
  - Back and Forward
  - Bookmarks menu
  - Toolbars
  - Side pane

* Navigation windows are basically the same as they used to be, but
  they don't save their geometry anymore.

* The default window size is much smaller.  This was to make the
  default object window size sane, and I just haven't gotten to 
  fixing it for nav windows.

Unfinished UI:

* I didn't finish porting the view as combo in the location bar.

* The "New Window" stuff isn't in the desktop context menu or the
  file menu.

* Lots of little bits - these things all need to be collected.

Some open UI questions:

* I moved "Open in New Window" to "Open With -> Navigation Window".  I 
  thought that this might reinforce the idea of the browser as a 
  separate app.  Any thoughts?

* Some ideas for differentiating the navigation window:
   - give it a constant, special icon rather than the icon of the
     contents
   - put a "- Nautilus" (or whatever) string after the current
     directory (or whatever the hig suggests for this sort of thing).

Implementation Notes:

* Unfinished parts are tagged with #if NEW_UI_COMPLETE.

* NautilusWindow has been split into a NautilusWindow base class, 
  a NautilusObjectWindow subclass, and a NautilusNavigationWindow
  subclass.  NautilusDesktopWindow now derives from
  NautilusObjectWindow.

* NautilusNavigationMenu merges a new xml file into the same ui
  component.  This lets us keep separate files that use the same
  verbs.

* I sort of abused the open_location_* functions in the idl.  
  open_location_in_this_window -> "open location according to the 
    current window (new object window or this navigation window"
  open_location_prefer_existing -> "open location in new object
    window"
  open_location_in_new_window -> "open location in new navigation 
    window".

* nautilus-window-menus is pretty well separated between the different
  subclasses, but nautilus-window-manage-views is still very tied
  together - a lot of the nav stuff needs to be built in there.

* Some stuff is blocking on the views being able to find out what kind
of
  window they're sitting in.

Some open implementation questions:

* How do we want to change the idl?  Should we just stick with
  abusing the open_location_* rather than trying to change things?
  (it's worth noting that the old semantics of those functions
  don't make much sense now).

* How do we want views to figure out what kind of window they're in? 
  Ambient property for the control?  idl extension?

* Is it worth the bother of trying to cleanly subclass the navigation
  parts of manage-views?