Fix #720 - Re-organize archives template

- Move posts exists check and post navigation to index.php

- templates/content.php now only contains the post that's pulled
in from index.php

- Specific post format templates now properly work

index.php

@@ -1,5 +1,21 @@
 <?php get_template_part('templates/page', 'header'); ?>
-<?php
-  $format = have_posts() ? get_post_format() : false;
-  get_template_part('templates/content', $format);
-?>
+
+<?php if (!have_posts()) : ?>
+  <div class="alert">
+    <?php _e('Sorry, no results were found.', 'roots'); ?>
+  </div>
+  <?php get_search_form(); ?>
+<?php endif; ?>
+
+<?php while (have_posts()) : the_post(); ?>
+  <?php get_template_part('templates/content', get_post_format()); ?>
+<?php endwhile; ?>
+
+<?php if ($wp_query->max_num_pages > 1) : ?>
+  <nav class="post-nav">
+    <ul class="pager">
+      <li class="previous"><?php next_posts_link(__('&larr; Older posts', 'roots')); ?></li>
+      <li class="next"><?php previous_posts_link(__('Newer posts &rarr;', 'roots')); ?></li>
+    </ul>
+  </nav>
+<?php endif; ?>