Set system time

[bdowling]

This branch adds setting the hardware clock with setttimeofday(), such that standard time() functions will work; at least to return UTC time. It felt to me like that should be part of such a library rather than leaving it up to the caller to research/realize this is needed, but some may have different opinion.

I was only able to test this on esp8266 at this time, I don't have any reference if this works on other hardware.

Perhaps this should be made optional step, but for me doing this in the ntpUpdate() call works for my use case. (I was using the TLog to log message via syslog and it expects time() to work.)

I suppose if it was optional, some might want this to set hardware to localtime; since it happens frequently enough I suppose that'd be good enough for DST changes.