Update for version 0.23.
Update for version 0.23.

SheffieldML/forkedGPmat,SheffieldML/GPmat,SheffieldML/GPmat,TianpeiLuke/GPmat,TianpeiLuke/GPmat,SheffieldML/GPmat,SheffieldML/GPmat,SheffieldML/GPmat,SheffieldML/forkedGPmat,SheffieldML/forkedGPmat,SheffieldML/GPmat,TianpeiLuke/GPmat,TianpeiLuke/GPmat,SheffieldML/forkedGPmat,SheffieldML/forkedGPmat,SheffieldML/forkedGPmat,TianpeiLuke/GPmat,TianpeiLuke/GPmat