/**
  * Constructor
  *
  * @param string $tpl_dir Template directory. It must be set the first time you use the class
  * @return RainTPL
  */
 function RainTPL($tpl_dir = null, $tpl_compile_dir = null, $base_dir = null)
 {
     if ($tpl_dir) {
         RainTPL::$tpl_dir = $tpl_dir . (substr($tpl_dir, -1, 1) != "/" ? "/" : "");
     }
     if ($tpl_compile_dir) {
         RainTPL::$tpl_compile_dir = $tpl_compile_dir;
     }
     if ($base_dir) {
         RainTPL::$base_dir = $base_dir;
     }
 }