Timestamp bounds

[gmax9]

Hi,

https://github.com/LibtraceTeam/libtrace/blob/master/tools/tracesplit/tracesplit.c#L198

Does it make sense to set the equality check to >=?

Please correct me if I'm wrong here, but since -s and -e are defined as integers, covering a range of intervals will either result in packets potentially being missed or packets being double counted.