#463, move gh-pages to docs folder

docs/_includes/base.html

@@ -0,0 +1,9 @@
+<!-- http://ricostacruz.com/til/relative-paths-in-jekyll.html -->
+<!-- _includes/base.html -->
+
+{% assign base = '' %}
+{% assign depth = page.url | split: '/' | size | minus: 1 %}
+{% if    depth == 1 %}{% assign base = '.' %}
+{% elsif depth == 2 %}{% assign base = '..' %}
+{% elsif depth == 3 %}{% assign base = '../..' %}
+{% elsif depth == 4 %}{% assign base = '../../..' %}{% endif %}