rework source resource handling

- move class Smarty_Template_Source into its own file
- impelement all source processing into the classes it better belongs to

libs/sysplugins/smarty_resource_uncompiled.php

@@ -16,6 +16,13 @@
  */
 abstract class Smarty_Resource_Uncompiled extends Smarty_Resource
 {
+    /**
+     * Flag that it's an uncompiled resource
+     *
+     * @var bool
+     */
+    public $uncompiled = true;
+
     /**
      * Render and output the template (without using the compiler)
      *
@@ -38,4 +45,25 @@ abstract class Smarty_Resource_Uncompiled extends Smarty_Resource
         $compiled->timestamp = false;
         $compiled->exists = false;
     }
+
+    /**
+     * render compiled template code
+     *
+     * @param Smarty_Internal_Template $_template
+     *
+     * @return string
+     * @throws Exception
+     */
+    public function render($_template)
+    {
+        try {
+            ob_start();
+            $this->renderUncompiled($_template->source, $_template);
+            return ob_get_clean();
+        }
+        catch (Exception $e) {
+            ob_get_clean();
+            throw $e;
+        }
+    }
 }