New log message formatter.

I use this module in combination with docker and Splunk and the multi-line logs are not collected correctly.

The problem lies in the fact that messages that contain stacktrace contain /n/r in them and the log driver (https://docs.docker.com/config/containers/logging/splunk/) breaks them up.

Attached is a small patch that introduces new formatting to make the log system work properly with systems that poorly tolerate the newline (/n)

I have no idea if this is a widespread problem or just a problem for splunk ... I leave it to the maintainers to evaluate.