This patch makes it possible to configure keybindings in gtk_text.

The arrays control_keys and alt_keys are now local to the widget
(initialized to default) and can be accessed with 
gtk_text_get_(control|alt)_keys.

GtkTextFunction *gtk_text_get_control_keys (GtkText *text);
GtkTextFunction *gtk_text_get_alt_keys (GtkText *text);

The arrays can the be modified, e.g.

  GtkTextFunction *control_keys;


  control_keys = gtk_text_get_control_keys (GTK_TEXT (text));
  control_keys['c'-'a'] = comment_selection;
  control_keys['p'-'a'] = plain_selection;

  /* C-c  -- comment_selection, C-p -- plain_selection */

The key modifier arrays can also be assigned new arrays with
gtk_text_set_keys.

void       gtk_text_set_keys        (GtkText         *text,
				     GtkTextFunction *control_keys,
				     GtkTextFunction *alt_keys);

/mailund