added total bytes/bandwidth/packets formulas to nics

added total bytes/bandwidth/packets formulas to nics
cleaned up stability code and wrote some better help for stats.py
fixed sample bug in info.py

dev/ns_gige.cc:
dev/ns_gige.hh:
dev/sinic.cc:
dev/sinic.hh:
    add total bandwidth/packets/bytes stats
util/stats/info.py:
    fixed samples bug
util/stats/stats.py:
    cleaned up stability code and wrote a bit better help

--HG--
extra : convert_revision : cae06f4fac744d7a51ee0909f21f03509151ea8f