Contains logging behaviour.
Get the logger.
@note Will try to grab Rails’ logger first before creating a new logger
with stdout.
@example Get the logger.
Loggable.logger
@return [ Logger ] The logger.
Set the logger.
@example Set the logger.
Loggable.logger = Logger.new($stdout)
@param [ Logger ] logger The logger to set.
@return [ Logger ] The new logger.
[Validate]