Add test for Stereographic projection for real.
Add test for Stereographic projection for real.

tzapzoor/marble,tzapzoor/marble,tzapzoor/marble,tzapzoor/marble,quannt24/marble,tucnak/marble,probonopd/marble,tucnak/marble,tzapzoor/marble,quannt24/marble,tucnak/marble,probonopd/marble,quannt24/marble,tucnak/marble,probonopd/marble,probonopd/marble,quannt24/marble,tzapzoor/marble,quannt24/marble,quannt24/marble,probonopd/marble,quannt24/marble,tzapzoor/marble,tzapzoor/marble,tucnak/marble,probonopd/marble,tucnak/marble,probonopd/marble,tucnak/marble