I made a Logger that logs to slf4j. This is to optionally replace default logging that prints to stdout / stderr. This is specifically useful when liquibase is run inside an application (servlet or spring).
The project is hosted at https://bitbucket.org/bn3t/liquibase-slf4j.
If you would like add it as an extension to https://github.com/liquibase I would be delighted.
I hope you will find this useful.