use smarty3 as default template engine. add pluggable template system

include/ITemplateEngine.php

@@ -0,0 +1,11 @@
+<?php
+require_once 'boot.php';
+
+
+/**
+ * Interface for template engines
+ */
+interface ITemplateEngine {
+	public function replace_macros($s,$v);
+	public function get_markup_template($file, $root='');
+}