returned comments on repeater (minor)
returned comments on repeater (minor)

Might want to change the suggested test (because zcm-spy wasn't
behaving):
1. examples/build/cpp/pub
2. examples/build/cpp/sub udpm://224.255.76.67:7667?ttl=0
3. zcm-repeater -s ipc -d udpm://224.255.76.67:7667?ttl=0

ZeroCM/zcm,ZeroCM/zcm,ZeroCM/zcm,ZeroCM/zcm,ZeroCM/zcm,ZeroCM/zcm