task/ta-npi-017-14 -- report filename needs to be based on BU

nparcel/exporter.py
* update the report() and outfile() method signature to include the
  "identifier" argument for BU-specific filename creation
* outfile() method now support an BU identifier in the filename creation

nparcel/exporterdaemon.py
* patched a bug in the sequence generator in the _start() method
task/ta-npi-017-14 -- report filename needs to be based on BU (cont)

nparcel/tests/test_exporter.py
* patch bug in the test_output_file_creation test