Minor v0.1.2 fixes.

- Don't show 'Update is available' when we can't reach github to check
- Don't show negative "seconds away" when the start of the next playlist
  is next week.  We assume anything with a starttime of more than 10
  minutes in the past is actually next week.
- Modify startup script to forcibly echo the IP address to the console
  during boot instead of logging to the startup.log file.

Thanks to MyKroft for noticing the first and last of these.