fixed issue with timezone support, if the timezone defined on the local
system is basically invalid, catch the die() from DateTime::TimeZone
and just override it to Chicago.

fixes: http://code.google.com/p/perfsonar-ps/issues/detail?id=819
fixed a dns result caching bug related to v4/v6 handling in lookup()
Fixed (again) issues found by George D. Uhl related processing the
traceroute timestamp data in order.  Now that the data is sorted,
there is no need to (in fact incorrectly) die() if we do not verify
that the timestamp is incrementing.  So, just remove some of the old
logic cruft left in place from that last change.