Improved logging

[crasanders]

AEPsych logs events such as messages being received or sent, but there are a number of improvements that could be made to logging to improve its utility:

• The server should have command line arguments to set the logging level and output file.
• Some logging messages should change their log level (e.g., model fitting time should be DEBUG, rather than INFO).
• Logging should be suppressed during testing to make test output easier to parse, and to prevent unnecessary writes to the log file.
• Different log level messages could be color-coded to make it easier to find errors (e.g., INFO could be green, ERROR red).