Extract the generic part of decode_alarm.[ch] into a new file bits1to14.[ch]
This makes it easier to accommodate for other contents (like Meteotime).

Update consumers (mainloop.c, dcf77pi.c and dcf77pi-analyze.c)
Generalize README.md a bit.
Use color for German civil warnings and Meteotime weather messages, fix displaying of buffer.
Align displaying of third-party information.