Fixed bugs 4385 (Nautilus doesn't gracefully handle deleting
	in-use image file), 3240 (reloading a directory doesn't update
	directory counts of the entries) and 4683 (embedded text on icon
	isn't updated when text changes) by implementing forgetting of
	file attributes and using it when appropriate.

	Also fixed various other bugs cought by testing of these fixes or
	reading the code.

	* libnautilus-extensions/nautilus-file.c:
	(nautilus_file_forget_attributes): New function that makes the
	file forget the specified attributes, including cancelling
	possible in-progress I/O for them, and kicking off new I/O if
	anyone is monitoring any of the attributes or has a pending
	call_when_ready.
	(nautilus_file_forget_attributes_internal): Forget all attributes
	of this file, *not* including cancelling in-progress I/O, or
	kicking off new I/O. This is for the benefit of NautilusDirectory
	being able to forget the attributes of all files it is monitoring
	at one go.
	(nautilus_file_forget_all_attributes): Forget all attributes of
	this file, including cancelling in-progress I/O, and kicking off
	new I/O.
	(forget_directory_count, forget_deep_counts, forget_mime_list,
	forget_top_left_text, forget_file_info, forget_activation_uri):
	Helper functions to forget individual attributes.
	(nautilus_file_forget_activation_uri): Removed as obsolete.
	(destroy): use `nautilus_g_list_free_deep' to free the mime list.

	* libnautilus-extensions/nautilus-directory-notify.h: Remove
	prototype for `nautilus_file_forget_activation_uri'.

	* libnautilus-extensions/nautilus-file-private.h: Prototype
	`nautilus_file_forget_attributes_internal'.

	* libnautilus-extensions/nautilus-file.h:
	`nautilus_file_forget_attributes' and
	`nautilus_file_forget_all_attributes'.

	* libnautilus-extensions/nautilus-link.c
	(nautilus_link_local_set_link_uri): Use
	`nautilus_file_forget_attributes', not
	`nautilus_file_forget_activation_uri' to ensure reload of the
	activation URI.
	(forget_file_activation_uri): Helper function for the above.

	* libnautilus-extensions/nautilus-directory-async.c
	(nautilus_directory_cancel_loading_file_attributes): Function to
	cancel in-progress I/O for a given set of attributes but only if
	it is in progress for the specified file. This function is used to
	implement part of `nautilus_file_forget_attributes'.
	(cancel_directory_count_for_file, cancel_deep_counts_for_file,
	cancel_mime_list_for_file, cancel_top_left_text_for_file,
	cancel_file_info_for_file, cancel_activation_uri_for_file): Helper
	functions for the above.
	(nautilus_directory_force_reload): Add a `file_attributes'
	argument and make sure to forget the specified
	attributes. Forgetting the attributes fixes bugs 3240 and 4683.
	(nautilus_directory_forget_file_attributes): Function to forget
	the specified attributes for all files. It makes sure to only
	cancel and kick off new I/O once.
	(cancel_loading_attributes): helper function for the above that
	cancels in-progress loads for the specified attributes, regardless
	of for what file.
	(request_is_satisfied): The request is not satisfied if the
	request calls for top left text and the file lacks it.
	(top_left_read_callback): Set 1got_top_left_text' field of the
	NautilusFile to TRUE. This problem was masked by the problem with
	`request_is_satisfied' fixed above.
	(set_up_request_by_file_attributes): Make sure to request the
	file_info as well if top left text is requested, since
	applicability of top left text depends on the mime type.
	(get_info_callback): Mark the file gone if we get
	GNOME_VFS_ERROR_NOT_FOUND; we can only get this error for files
	gnome-vfs should know about but that do not exist. This is needed
	to detect files that are removed on a reload.

	* libnautilus-extensions/nautilus-directory-private.h: Update
	prototype for `nautilus_directory_force_reload'; Prototype
	`nautilus_directory_cancel_loading_file_attributes'

	* libnautilus-extensions/nautilus-vfs-directory.c
	(vfs_file_monitor_add): Pass the file attributes to
	`nautilus_directory_force_reload' since it now wants them.

	* src/nautilus-window-manage-views.c
	(viewed_file_changed_callback): Cancel location change before
	closing the window, since detecting the file is gone is now likely
	to happen in the middle of an in-progress reload, and we get
	crashes if this is not done.
	(nautilus_window_begin_location_change): If we're doing a reload,
	forget all file attributes of the NautilusFile for the currently
	viewed location. This is to make sure we detect if the file is
	gone, and also update the sidebar panel icon and other info
	appropriately. This fixes bug 4385.