change header.html to menu.html

make a few updates to modularity of the layout, for better interoperability with autocat3

_includes/menu.html

@@ -0,0 +1,47 @@
+    <nav role="navigation">
+      <a href="/index.html" class="no-hover">
+        <img class="logo" src="/gutenberg/pg-logo-129x80.png" alt="Project Gutenberg" draggable="false">
+      </a>
+      <label for="show-menu" class="show-menu"><img src="/gutenberg/menu-icon.png" class="menu"></label>
+      <input type="checkbox" id="show-menu" role="button">
+      <!--<a href="#" class="show-menu"></a>-->
+
+      <ul id="menu">
+       <!--<li><a href="/ebooks/index.php">Find a Book</a></li>-->
+       <li><a href="/ebooks/">Find an eBook</a></li>
+        <li><a href="#">How to Help</a></li>
+        <li><a href="#">Help</a>
+          <ul class="hidden">
+            <li><a href="/help/mobile.html">Mobile How-To</a></li>
+            <li><a href="#">Sub-2</a></li>
+            <li><a href="#">Sub-3</a></li>
+          </ul>
+        </li>
+        <li><a href="#">About</a>
+          <ul class="hidden">
+            <li><a href="/about/history.html">About Us</a></li>
+            <li><a href="/policy/privacy_policy.html">Privacy Policy</a></li>
+            <li><a href="/about/contact_information.html">Contact Us</a></li>
+          </ul>
+        </li>
+        <li><a href="/donate/">Donate</a></li>
+      </ul>
+
+      <form method="get" action="/ebooks/search/"
+      accept-charset="utf-8" enctype="multipart/form-data" class="searchbox">
+          <input type="text" value="" id="menu-book-search" name="query" class="searchInput" title="" alt="undefined string" tabindex="20" size="20" maxlength="80"
+          placeholder="Search for Books"/>
+          <input type="submit" name="submit_search" value="Search" style="vertical-align:middle;">
+      </form>
+
+      <div class="donate">
+        <form action="https://www.paypal.com/cgi-bin/webscr" method="post" target="new">
+          <p>Project Gutenberg appreciates your donation! Learn <a href="/donate/">Why Donate?</a> Click here to:</p>
+          <input type="hidden" name="cmd" value="_s-xclick" />
+          <input type="hidden" name="hosted_button_id" value="XKAL6BZL3YPSN" />
+          <input class="donbtn" type="image" src="/gutenberg/en_US.gif"
+           name="submit" alt="PayPal-The safer, easier way to pay online!" />
+        </form>
+      </div>
+
+    </nav>