task/ta-nst-011-03 -- refactor the cleanse to incorporate date columns

nparcel/uncollected.py
* added "JOB_TS", "CREATED_TS", "NOTIFY_TS" and "PICKUP_TS"
  to the _cleanse() method column patch list
* refactor the escape format ('="xxx"') in the _cleanse() method to
  present correctly in Excel
task/ta-nst-008-15 -- update processed_ts before running report

nparcel/table/agent_stocktake.py
* updated the reference_sql() method to exclude processed_ts from the
  query
* new method update_processed_ts_sql() to update the
  agent_stocktake.processed_ts column

nparcel/uncollected.py
* updated the process() method to set the agent_stocktake.processed_ts
  column before starting processing