Restructure theme, use autoloader

templates/partials/content.php

@@ -0,0 +1,9 @@
+<article <?php post_class(); ?>>
+  <header>
+    <h2 class="entry-title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
+    <?php App\template_part('partials/entry-meta'); ?>
+  </header>
+  <div class="entry-summary">
+    <?php the_excerpt(); ?>
+  </div>
+</article>