GeographicLib 2.1 (released 2022-06-09)

Changes between 2.1 (released 2022-06-09) and 2.0 versions:

• Improve the accuracy of the area calculations in GeodesicExact
  and the Planimeter utility with the -E option. This now gives
  full double precision accuracy for b/a in [0.01, 100] or f in
  [-99, 0.99]. (Previously the range for full accuracy was b/a in
  [0.5, 2].) The method involves a direct computation of the
  Fourier series for the integrand of area integral which then
  allows the integral to be evaluated.

• Add a new class DST for doing discrete sine transforms. This is
  mainly for "internal" use, to compute the area in GeodesicExact.
  Internally, this uses the kissfft package by Mark Borgerding.

• Fix various warnings from Visual Studio about arithmetic involving
  enums.

• Minor improvement in the logic for the geodesic inverse problem
  to address a slow down that can occur with
  GEOGRAPHICLIB_PRECISION = 5 due to the time it takes to
  calculate, for example, sin(10^(10^8)) accurately.