Fixes logger for AuditLoggerInfo when none is provided (#109)
* Fix logger for AuditLoggerInfo when none is provided.
This commit fixes an issue with the AuditLoggerInfo structure where
a user may fail to provide a logger at the time the struct is instantiated.
The method logger() for the AuditLoggerInfo structure handles this case by
instantiating a default logger that logs to Stderr if no logger instance
is provided. The logger() method simply needs to be used, and this commit
adds that functionality.