update router tag according to Sindre's suggestion

router_tag.imba

@@ -5,10 +5,19 @@ require './not_found/not_found'
 
 tag router
 
+	prop component watch: yes
+
 	def setup
 		@r = R
-		@t = Imba:TAGS
+		@component = null
+		@cache = {}
+
+	def componentDidSet val, prev
+		removeChild(prev) if prev
+		appendChild(val) if val
+		self
 
 	def render
-		self:__:A = self:__:A || {}
-		<self> ( self:__:A[@r:view] || self:__:A[@r:view] = @t[@r:view.toUpperCase]() ).end
+		var view = @data || @r:view
+		component = @cache[view] ||= Imba.createElement(view,null,null,self)
+		component.end