Color log output.

This depends on #6, so if you like it, make sure to merge it after #6.  If you don't like #6, then I can rework this without much difficulty.  It's just that they both touch the same areas, and will conflict.

At any rate, I mentioned the idea quite a while ago and finally got some cycles to try it out.  There may be more color configuration knobs than necessary, but I think I like the result.  Hopefully, you do too. :-)