Replace get_module_setting/set_module_setting for WT 1.6
Replace WT_Site::preference with WT_Site::getPreference for WT 1.6
Replace get_user_setting with $user->getPreference
Replace set_user_setting and AddToLog(..., 'auth')
Switch to addConfigurationLog and addErrorLog
Use Auth::login
requireAdminLogin => restrictAccess(\WT\Auth::isAdmin())
get_module_setting => $this->getSetting in admin.php