Add calling class and function information in logs. #1634

Issue #1634 
Add the name of the class and function where a Log::write is called into log messages.

Old log message format:
2013-01-22 23:03:34 ERROR - Space name, backstages, generated non-object

New log message format:
2013-01-22 23:03:34 ERROR - Podioconnect::get_space_id - Space name, backstages, generated non-object