[9fans] latency & jitter resistant stats

[erik quanstrom]

i was having some trouble with stats reporting higher
ethernet throughput when my connection to the cpu
server was getting busy. here's a little experiment that
works around the problem by reducing the sleep time
by the time it takes to make the samples. as a secondary
connection, if the sampling time exceedes 1/4 of the
sample rate, the sample time is doubled. the sample
rate will be reduced if the sample rate goes to 1/32 of
the adjusted rate.

/n/sources/contrib/quanstro/src/stats.c

while this was quick and easy and fairly accurate, a
better solution would be to calculate the rate on the remote.

i also switched the ethernet scale to be prop. to link
speed rather than the number of processors and added
tracing for /net.alt/ether1.

there was also a bug that will divide by zero if
sleepsecs < 1.0 when displaying ethernet errors.

also included, a fix for numbers too big to fit in 32 bits,
such as the packet counts in /net*/ether?/stats. i submitted
this fix as a patch.

- erik