Laggy Network Bugfix
Fixed a bug (NullPointerException) which only appears in high-latency network conditions.
If no NTP responses meet the minimum criteria for root delay, root dispersion and round-trip delay,
then the "best response" method is forced to choose the 'best' response from an array of null TimeData
s.
Previously in this case, it chose the -1th element, causing a NullPointerException.
Now, it just returns null.