[Bug 2464] Adding timestamp to debug messages (log.c:do_log)

[Mark D. Baushke]

Diff updated with suggested changes (also, making the timestamp format
ISO8601 compliant).

Hmmm... full IOS8601 compliance would include the timzeone so the format
string would be "%Y%m%dT%H%M%S%z" (and need to increase the size of the
timebuf[20] by one byte or you would use gmtime() instead of localtime()
and the format string "%Y%m%dT%H%M%SZ". I think gmtime() may be simpler.

	-- Mark