Enable logging file

[dwang2]

It'd be better to take command option to output logs to a file.

[DirectXMan12]

We already use the Python standard library's logging framework, so this should be as easy as adding a command line option for switching the logger to a file logger.

[jeffforbes]

I already made patches for controlling the location of the log file and making sure all of the messages went to the same location and put them in a different issue report: #193

I am not sure how to get them into the correct place for eventual incorporation into the code base.