Fix stats for small pcaps and ctx->abort check for limited loops

Stats weren't printed in 4.1.0beta for really small pcaps, the ctx->stats last time/print bits should be initialized once per program run, not per send_packets() call . Not 100% sure I got the ideal location, but works for my test case.

Also, as noted in my patch comment, I originally got the location of the ctx->abort check wrong for limited loops.