Changes associated with gap filling from BIOS2 and ACCESS:
 - gap filling from BIOS2 now implemented
 - changed fixing of time gaps, no able to remove
   duplicate records
 - several changes to handling of time in access2nc.py
 - moved time_zone dictionary from qcutils.get_timezone
   to constants.py
 - implemented search of time_zone dictionary if
   qcutils.get_UTCfromlocaltime unable to find time_zone in
   global attributes
 - sundry other cganes along the way