remove scalalogging from dependencies

@dlwh This PR remove scalalogging from breeze's dependencies. The main reason is that scalalogging is not backward compatible. No matter which version we use in breeze, it may conflict with other components of a project. What do you think?

Some related PRs in Spark:

1. https://github.com/apache/spark/pull/940
2. https://github.com/apache/spark/pull/1208

thanks. I've been lazy and haven't removed that one.