Improve and test support for customized templates

Change-Id: I7209c247b01dc06078d84c18e0a7beed80c6a62c
diff --git a/t/custom/intro.html.ep b/t/custom/intro.html.ep
new file mode 100644
index 0000000..0a29e55
--- /dev/null
+++ b/t/custom/intro.html.ep
@@ -0,0 +1,6 @@
+% layout 'main', sidebar_active => 1;
+
+
+<div class="intro">
+  <h2>This is a custom intro page!</h2>
+</div>