i3 config: Stop using py3status & some fixes

- Force sup and finch to use a typical white on black colour scheme in
  the terminal, as they have poor contrast otherwise.

- Change i3status to use a 12-hour time format.

- py3status doesn't quite do what I want, so drop it for now. I might
  consider bringing it back for the music player status since that will
  be polling anyway... For other things I'd rather use a select loop.
i3 config: Some changes for my thinkpad

I'm going to need to come up with a way to switch out parts of the
config for each machine I use, but for now just change a couple of
things to suit my thinkpad laptop.