Add LIBGEOTIFF_MAJOR_VERSION, LIBGEOTIFF_MINOR_VERSION, LIBGEOTIFF_PATCH_VERSION, LIBGEOTIFF_REV_VERSION, and LIBGEOTIFF_STRING_VERSION variables in geotiff.h, and autogenerate it

Add LIBGEOTIFF_MAJOR_VERSION, LIBGEOTIFF_MINOR_VERSION, LIBGEOTIFF_PATCH_VERSION, LIBGEOTIFF_REV_VERSION, and LIBGEOTIFF_STRING_VERSION variables in geotiff.h, and autogenerate it #23