ideas for logger enhancements

[ejaquay]

logger.cpp is a simple utility that writes events to a file or console. When code is not working right one of the fastest ways to locate the issue is logging.

Ideally logging statements would be removed once code is working but practically there is good reason to leave them in place and control their use with a compiler variable. Currently USE_LOGGING is defined for that purpose. When it is set all logging statements for all of VCC become active and the log becomes flooded with messages that are not of current interest to the developer. I think we shoud add an enhancenent that assigns a value to USE_LOGGING to classify which logging messages that are activated.