Make saved pseudodata match fitted pseudodata

Created by: scarlehoff

Closes #1513 (closed).

make_replica still gets called twice per group though, couldn't find a reasonable solution for that, seems a bit of a waste of CPU cycles but at least now they generate the same array.

I guess it would be good if #1503 fixed that somehow

Also, in the topic of #1503, I've been running a lot make_replica in my laptop to fix this issue and I don't find it particularly slow.