Avoid NPE when less than 3 points left

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36866 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Refactor setting willingCoords / willingDirection to null

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36867 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e