Remove old plugin system and docs for it

Adapted from:
3860e7b99f (diff-c949f93d03f44a4217d7a138f9e2e54a)

docs/reference/Makefile.am

@@ -46,8 +46,6 @@ IGNORE_HFILES=		\
 	xed-documents-panel.h			\
 	xed-io-error-message-area.h		\
 	xed-languages-manager.h		\
-	xed-object-module.h			\
-	xed-plugin-manager.h			\
 	xed-plugins-engine.h			\
 	xed-prefs-manager-private.h		\
 	xed-session.h				\

docs/reference/xed-docs.sgml

@@ -1,5 +1,5 @@
 <?xml version="1.0"?>
-<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" 
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
                "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
 <book id="index" xmlns:xi="http://www.w3.org/2003/XInclude">
   <bookinfo>
@@ -17,7 +17,6 @@
     <xi:include href="xml/xed-message.xml"/>
     <xi:include href="xml/xed-notebook.xml"/>
     <xi:include href="xml/xed-panel.xml"/>
-    <xi:include href="xml/xed-plugin.xml"/>
     <xi:include href="xml/xed-print-job-preview.xml"/>
     <xi:include href="xml/xed-print.xml"/>
     <xi:include href="xml/xed-progress-message-area.xml"/>

docs/reference/xed-sections.txt

@@ -236,30 +236,6 @@ XED_IS_PANEL_CLASS
 XED_PANEL_GET_CLASS
 </SECTION>
 
-<SECTION>
-<FILE>xed-plugin</FILE>
-<TITLE>XedPlugin</TITLE>
-XedPlugin
-xed_plugin_activate
-xed_plugin_deactivate
-xed_plugin_update_ui
-xed_plugin_is_configurable
-xed_plugin_create_configure_dialog
-XED_PLUGIN_REGISTER_TYPE
-<SUBSECTION Standard>
-XED_PLUGIN
-XED_IS_PLUGIN
-XED_TYPE_PLUGIN
-xed_plugin_get_type
-XED_PLUGIN_CLASS
-XED_IS_PLUGIN_CLASS
-XED_PLUGIN_GET_CLASS
-XED_PLUGIN_REGISTER_TYPE_WITH_CODE
-XED_PLUGIN_REGISTER_TYPE
-XED_PLUGIN_DEFINE_TYPE_WITH_CODE
-XED_PLUGIN_DEFINE_TYPE
-</SECTION>
-
 <SECTION>
 <FILE>xed-print-job-preview</FILE>
 XedPrintJobPreviewPrivate

docs/reference/xed.types

@@ -8,7 +8,6 @@
 #include "xed-message-type.h"
 #include "xed-notebook.h"
 #include "xed-panel.h"
-#include "xed-plugin.h"
 #include "xed-progress-message-area.h"
 #include "xed-statusbar.h"
 #include "xed-tab.h"
@@ -24,7 +23,6 @@ xed_message_bus_get_type
 xed_message_type_get_type
 xed_notebook_get_type
 xed_panel_get_type
-xed_plugin_get_type
 xed_progress_message_area_get_type
 xed_statusbar_get_type
 xed_tab_get_type