Wrap templates located outside the theme

Wrapper will now pass through $template if locate_template() turns up zero
results.

src/filters.php

@@ -49,5 +49,5 @@ add_filter('template_include', function ($main) {
     if (!is_string($main) || !(string) $main) {
         return $main;
     }
-    return template_wrap(new Wrapper(basename($main)));
+    return template_wrap(new Wrapper($main));
 }, 109);

src/lib/Sage/Template/Wrapper.php

@@ -60,6 +60,6 @@ class Wrapper implements WrapperInterface
     public function getTemplate()
     {
         $template = apply_filters('sage/unwrap_' . $this->slug, $this->template) ?: $this->template;
-        return locate_template($template);
+        return locate_template($template) ?: $template;
     }
 }