more taxonomy changes + separate header

too eepy to write a proper commit message

layouts/_default/LuaFunctions.html

@@ -1,9 +1,12 @@
 {{ define "main" }}
+    {{ partial "header.html" }}
     <article>
-        <a href="..">go up</a>
         <header>
             <h1><code>{{ .Title }}</code> – {{ .Description }}</h1>
         </header>
         {{ .Content }}
+        <footer>
+            {{ partial "categories.html" }}
+        </footer>
     </article>
 {{ end }}