Added tm_format_reltime() for formatting of relative time quantities.
Moved TIME_INFINITY to timer.h, so that it's publicly available.
Added functions for parsing and formatting of dates.
Added comment explaining `now'.
Replaced remaining references of clock_t by bird_clock_t.
Whee, multicast sockets work!
Implemented recurrent timers.
Implemented timers. Using bird_clock_t for absolute time from now...
The library is now glued together from generic and OS-dependent partsby the `mergedirs' script. Few more IP address manipulation functionsand some fixes.