Extracted page support from cms_node_module, and add a proper CMS_PAGE_MODULE.

- now, the CMS_PAGE_MODULE has to be declared in the related CMS_SETUP via CMS_EXECUTION.
   (See demo for example)

Improved the export facilities.
  Implemented blog and page export.
Added import facilities.
  Implemented blog and page import.

Improved node revision web interface (allow to edit a past revision, in order to restore it as latest revisionm i.e current).
Removed specific tag from blog module, and reuse the taxonomy module for that purpose.

Added WIKITEXT module that provide a WIKITEXT_FILTER, so now we can have wikitext content.
   - for now, no support for wiki links such as [[Foobar]].

modules/blog/cms_blog.e

@@ -9,8 +9,7 @@ class
 inherit
 	CMS_NODE
 		redefine
-			make_empty,
-			import_node
+			make_empty
 		end
 
 create
@@ -24,23 +23,6 @@ feature {NONE} -- Initialization
 			Precursor
 		end
 
-feature -- Conversion
-
-	import_node (a_node: CMS_NODE)
-			-- <Precursor>
-		do
-			Precursor (a_node)
-			if attached {CMS_BLOG} a_node as l_blog then
-				if attached l_blog.tags as l_tags then
-					across
-						l_tags as ic
-					loop
-						add_tag (ic.item)
-					end
-				end
-			end
-		end
-
 feature -- Access
 
 	content_type: READABLE_STRING_8
@@ -60,11 +42,6 @@ feature -- Access: node
 			-- Format associated with `content' and `summary'.
 			-- For example: text, mediawiki, html, etc
 
-feature -- Access: blog
-
-	tags: detachable ARRAYED_LIST [READABLE_STRING_32]
-			-- Optional tags
-
 feature -- Element change: node
 
 	set_content (a_content: like content; a_summary: like summary; a_format: like format)
@@ -74,39 +51,5 @@ feature -- Element change: node
 			format := a_format
 		end
 
-feature -- Element change: blog		
-
-	add_tag (a_tag: READABLE_STRING_32)
-			-- Set `parent' to `a_page'
-		require
-			not a_tag.is_whitespace
-		local
-			l_tags: like tags
-		do
-			l_tags := tags
-			if l_tags = Void then
-				create l_tags.make (1)
-				tags := l_tags
-			end
-			l_tags.force (a_tag)
-		end
-
-	set_tags_from_string (a_tags: READABLE_STRING_32)
-		local
-			t: STRING_32
-		do
-			tags := Void
-			across
-				a_tags.split (',') as ic
-			loop
-				t := ic.item
-				t.left_adjust
-				t.right_adjust
-				if not t.is_whitespace then
-					add_tag (t)
-				end
-			end
-		end
-
 end