rename radvdion.c readn_writen.c
syscalls_test.c: flesh out radvd_bind

just return 0 for success
add config.h.in~ to .gitignore
always write a pid file if specified on command line

When running tests, we need a reliable way to find the radvd pid so we can
reliably kill radvd.  Write a pidfile, or die, if the -p option is passed
to radvd.
add trivial radvd run check
timer.c: prune expired

coverage testing exposed the function, expired, as never called.
6lowpan: add notes to CHANGES and radvd.8.man

Conflicts:
	CHANGES
use ppoll to prevent signal race condition
trivial.sh: run radvd longer (0.5s)

This test was running too quickly and not doing enough because of it.
syscalls_test.c: flesh out radvd_sendmsg a little
kickoff_adverts: schedule the iface even if send_ra_forall fails

I've seen the problem a few times.  Maybe send_ra_forall should go ahead
and reschedule the interface so the calling code doesn't have to.