AST Version 8.4.0

• The PAL library files included in the AST distribution have been updated
  to PAL version 0.9.7.
• Multiple identical NormMaps in series will now be simplified to a
  single NormMap.
• A NormMap that encapsulates a basic Frame will now be simplified to a
  UnitMap.
• The astTimeAdd (AST_TIMEADD) method of the TimeMap class now include an
  extra argument that gives the number of values supplied in the arguments
  array. Note, any existing code that uses this method will need to be
  changed.
• The astSlaAdd (AST_SLAADD) method of the SlaMap class now include an
  extra argument that gives the number of values supplied in the arguments
  array. Note, any existing code that uses this method will need to be
  changed.
• The astSpecAdd (AST_SPECADD) method of the SpecMap class now include an
  extra argument that gives the number of values supplied in the arguments
  array. Note, any existing code that uses this method will need to be
  changed.
• If the astMapRegion (AST_MAPREGION) method is used to map a Region into
  a new Frame that has fewer axes than the original Region, and if the
  inverse transformation of the supplied Mapping does not specify a value
  for the missing axes, then those axes are removed entirely from the
  Region. Previously they were retained, but supplied with bad values. This
  affects the number of mesh points per axes for such Regions, and so
  affects the accuracy of overlap determination.