Code: More explicit type naming

[Andy Nowacki]

Consider changing the names of types such as MtCcvf to be more explicit (e.g., MTCrossCovarianceFunction if that’s what it’s short for). It seems that users don’t need to ever construct these types themselves, so I think the verbosity will be very helpful in describing what the output is.

[Charlotte Haley]

See here for readable types.

[Andy Nowacki]

The new types look very nice and hopefully more easily comprehensible to users. This addresses my point and can be closed.