Added sample feed and namespace

Author: magneticflux-

src/main/kotlin/com/github/magneticflux/rss/namespaces/atom/elements/AtomRss.kt

@@ -0,0 +1,3 @@
+package com.github.magneticflux.rss.namespaces.atom.elements
+
+const val ATOM_REFERENCE = "http://www.w3.org/2005/Atom"

src/test/resources/com/github/magneticflux/rss/sample_atom.xml

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="utf-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+    <title type="text">dive into mark</title>
+    <subtitle type="html">
+        A &lt;em&gt;lot&lt;/em&gt; of effort
+        went into making this effortless
+    </subtitle>
+    <updated>2005-07-31T12:29:29Z</updated>
+    <id>tag:example.org,2003:3</id>
+    <link href="http://example.org/" hreflang="en" rel="alternate" type="text/html" />
+    <link href="http://example.org/feed.atom" rel="self" type="application/atom+xml" />
+    <rights>Copyright (c) 2003, Mark Pilgrim</rights>
+    <generator uri="http://www.example.com/" version="1.0">
+        Example Toolkit
+    </generator>
+    <entry>
+        <title>Atom draft-07 snapshot</title>
+        <link href="http://example.org/2005/04/02/atom" rel="alternate" type="text/html" />
+        <link href="http://example.org/audio/ph34r_my_podcast.mp3"
+            length="1337"
+            rel="enclosure"
+            type="audio/mpeg" />
+        <id>tag:example.org,2003:3.2397</id>
+        <updated>2005-07-31T12:29:29Z</updated>
+        <published>2003-12-13T08:29:29-04:00</published>
+        <author>
+            <name>Mark Pilgrim</name>
+            <uri>http://example.org/</uri>
+            <email>f8dy@example.com</email>
+        </author>
+        <contributor>
+            <name>Sam Ruby</name>
+        </contributor>
+        <contributor>
+            <name>Joe Gregorio</name>
+        </contributor>
+        <content type="xhtml" xml:base="http://diveintomark.org/" xml:lang="en">
+            <div xmlns="http://www.w3.org/1999/xhtml">
+                <p>
+                    <i>[Update: The Atom draft is finished.]</i>
+                </p>
+            </div>
+        </content>
+    </entry>
+</feed>