Fix root YAML variable in bin/lesson_initialize.py

Close #186

LICENSE.md

 ---
 layout: page
 title: "Licenses"
-permalink: /license/
+root: .
 ---
 ## Instructional Material
 

bin/lesson_initialize.py

@@ -263,6 +263,7 @@ FIXME: home page introduction
 ROOT_REFERENCE_MD = '''\
 ---
 layout: reference
+root: .
 ---
 
 ## Glossary
@@ -274,6 +275,7 @@ ROOT_SETUP_MD = '''\
 ---
 layout: page
 title: Setup
+root: .
 ---
 FIXME
 '''
@@ -281,6 +283,7 @@ FIXME
 ROOT_AIO_MD = '''\
 ---
 layout: page 
+root: .
 ---
 <script>
   window.onload = function() {