Changes associated with implmenting gap filling using ACCESS data:
 - modified all creation and retrieval routines (eg GetSeriesasMA,
   MakeEmptySeries etc) so that they now return the attribute
   dictionary as well as the data and the QC flag
 - implmented automatic correction for lag between ACCESS and
   tower data'
 - implmented choice of manual date setting or automatic (no. of
   days, monthly or yearly) in ACCESS GUI