task/ta-npe-002-29 -- comms not sent out on certain days:
config support

nparcel/b2cconfig.py
* new attribute skip_days to hold a list of day names that should not
  send out notification comms

nparcel/conf/nparceld.conf
* placeholder for new config item skip_days

nparcel/reminderdaemon.py
* new method skip_days to check whether comms is configured to
  skip current day of week
* updated process() method to skip comms on a skip day