Preliminary code to fix #1570 - log access to videos to file, via the logging module.

We are routing these requests through the central server, but not collecting any data on them.  To start, to avoid database overhead, we'll log info (time and IP of download request) to a file.

To start, I'll log to the console.  Next step is to log to a file, following config options here:
https://docs.djangoproject.com/en/dev/topics/logging/

Submitting now to see if anybody could pick up and make any suggestions / help complete things :)