Remove print statements

We prefer to use logging.info() or logging.critical(). If it is necessary to avoid the logging mechanism use sys.stdout.write() or sys.sterr.write().

Right now there are various print statements in the HPOlib:
https://github.com/automl/HPOlib/search?utf8=%E2%9C%93&q=print

Start with the repository-wide print search linked in the issue and review each matching HPOlib location to determine whether logging.info(), logging.critical(), sys.stdout.write(), or sys.sterr.write() is appropriate. Done means the identified print statements have been handled consistently; no tests or specific files are named in the issue.

Written by the indexing model from the issue text.