run more rsync threads at the same time by default
run more rsync threads at the same time by default

Using the three testbed TALs:
$ time ./run_scripts/chaser.sh
...
real    13m6.998s
user    0m1.040s
sys     0m4.592s

rhansen/rpstir,rhansen/rpstir,rhansen/rpstir,rhansen/rpstir,rhansen/rpstir