Scantable constructor

This loads all of the data from filename into the scantable object scans and averages all the data within a scan (i.e. the resulting scantable will have one row per scan). The recognised input file formats are RPFITS, SDFITS (singledish fits), ASAP's scantable format and aips++ MeasurementSet2 format.

Example usage:

  ASAP>scan = scantable('2004-11-23_1841-P484.rpf')

  # Don't scan average the data
  ASAP>scan = scantable('2004-11-23_1841-P484.rpf', average=False)