* Remove clipdrop->dnd_target_state, it's not used anymore
* Remove non-functioning _gdk_dropfiles_store(), store dropfiles
  list in GdkWin32Drop instead
* Fix multiple comment typos
* Fix _gdk_win32_get_clipboard_format_name_as_interned_mimetype() to
  leave names that look like mime/types alone
* Refactor _gdk_win32_add_w32format_to_pairs() to populate
  GdkContentFormatsBuilder directly, instead of making a GList
* Rename context -> drag (still using GdkDragContext type,
  but [almost?] all variables and comments say "drag" now)
* Rename GdkDropContext -> GdkDrop
* Rename some parameter names for clarity
* Rewrite local protocol to look more like OLE2 protocol
  instead of mirroring the structure of the X11 API.
* Add handle_events field to GdkWin32DragContext,
  to shut off event handling (temporary fix until GTK is patched up)
* Remove _gdk_win32_drag_context_find() - the drag object is stored
  in GdkDrop instead. Use _gdk_win32_find_drag_for_des...