namespace cleanups.

1999-06-21  Michael Natterer  <mitschel@cs.tu-berlin.de>

	* app/context_manager.c: namespace cleanups.

	* app/commands.[ch]
	* app/menus.c: moved the "Toggle Selection" menu entry to "View",
	sprinkled some separators and made the layers/channels/paths popup
	menus consistent with Tigert's last ops buttons change.

	* app/fileops.c
	* app/plug_in.c: check for gdisplay_active() returning NULL in
	some more places.

	* app/[all tool related files]:

	- Turned the ToolAction and ToolState #define's into typedef'ed
	  enums, so the compiler can do some more sanity checking.
	- Removed one more unused global variable "active_tool_layer".
	- Removed some #include's from tools.c.
	- Standardized the individual tools' structure names.
	- Moved showing/hiding the tool options to separate functions.
	- Stuff...

	* app/commands.c
	* app/disp_callbacks.c
	* app/gdisplay.c
	* app/tools.c: fixed the segfaults which happened when the image
	of one of the tools which have dialogs (levels/posterize/...) was
	deleted. My approach was to do stricter sanity checking and to set
	some gdisplay pointers correctly where appropriate, so I can't
	tell exactly where the bug was.
	The curves tool now(??) updates on every _second_ display change
	only, which is really obscure.
	Finding/changing the display to operate on should definitely be
	done by connecting to the user context's "display_changed"
	signal.

	* app/gimpset.c: emit the "remove" signal _after_ removing the
	pointer from the set. If this was not a bug but a feature, please
	let me know, we'll need two signals then.

app/plug-in/plug-in-params.c

@@ -1218,6 +1218,7 @@ plug_in_repeat (int with_interface)
   if (last_plug_in)
     {
       gdisplay = gdisplay_active ();
+      if (!gdisplay) return;
 
       /* construct the procedures arguments */
       args = g_new (Argument, 3);
@@ -2286,6 +2287,7 @@ plug_in_callback (GtkWidget *widget,
 
   /* get the active gdisplay */
   gdisplay = gdisplay_active ();
+  if (!gdisplay) return;
 
   proc_rec = (ProcRecord*) client_data;