Log Message:
geography/gama: Update to 2.18

* Changes in release 2.18 (2022-04-09)

New conversion class K2gkf (lib/krumm) with accompanying program
krumm2gama-local and the testing suite for converting input data
format used in the text book "Geodetic Network Adjustment Examples" by
Friedhelm Krumm, Geodätisches Institut Universität Stuttgart, 2020.

Not all input data in Krumm Format can be converted to GNU Gama,
i.e. to the adjustment program gama-local input XML:

* scale factor is not implemented in gama-local adjustment

* gama-local does not enable fixing only x coordinate (or y
  coordinate) for 2D free network to remove singularity. This kind
  of regularization has very little practical meaning. Technically
  it would be possible to enable this feature in gama-local, but it
  is questionable if the outcome would not enable more confusion
  than possible outcome. Adustment should not be dependent on the
  coordinate system used.

* gama-local does not deduce that an azimuth to the unknown point
  P can be combined with some angle pointing to the P to create a
  new feigned azimuth. This is an interesting feature which may
  be implemented in some future version, namely in the gama-local
  stage of computing approximate coordinates.

* nonlinear conditions are not implemented in gama-local

* BLH coordinates are not supported in gama-local