Code reorg, helpers.go has been decomposed.

It started with wanting to move templates in template bundles and the
rest followed.  I did my best to start grouping related functions
together, but there are some that I missed.  There is also the method
Urlize that seems to be a special function used in both worlds.  I'll
need to revisit this method.

hugolib/site_test.go

@@ -3,9 +3,9 @@ package hugolib
 import (
 	"bytes"
 	"fmt"
+	"html/template"
 	"strings"
 	"testing"
-	"html/template"
 )
 
 var TEMPLATE_TITLE = "{{ .Title }}"