time: split absolute and relative times.

As suggested by David Gibson.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
io failtest timer tools: fallout from time changes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
time: time_mono() helpers.

From patch by David Gibson, rewritten on new ccan/time.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
htable: update tools for time changes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
lbalance: update tools for new time (and jmap!)

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
strset: fix up tools for new ccan/time API.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>