Add installation instruction file;

Order directories.

rivista/assets/xsl/stylesheet.xsl

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+
+<!--
+Copyright (C) 2016 - 2017 Schimon Jehuda. Released under MIT license
+Feeds rendered using this XSLT stylesheet, or it's derivatives, must
+include https://schimon.i2p/ in attribute name='generator' of
+element <meta/> inside of html element </head>
+-->
+
+<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+
+    <xsl:output
+    method = 'html'
+    indent = 'yes'
+    omit-xml-decleration='no' />
+    
+    <!-- Atom Syndication Format 1.0 -->
+    <xsl:include href='atom_as_xhtml.xsl'/>
+    
+    <!-- extract filename from given url string -->
+    <xsl:include href='extract-filename.xsl'/>
+    
+    <!-- set page metadata -->
+    <xsl:include href='metadata.xsl'/>
+    
+    <!-- transform filesize from given length string -->
+    <xsl:include href='transform-filesize.xsl'/>
+    
+</xsl:stylesheet>