PHP notice if class is not specified for logger

[stefan-r-meier]

If class name is not specified for logging, there is a php notice.

Example:

xContext::$log->log("test");

PHP Notice: Undefined index: class in /Volumes/FILES/smeier/Sites/protview/app/lib/xfm/lib/Core/Logger.php on line 111

Could you please fix this?

[damiencorpataux]

Thank you for reporting