Added annealing structure generation

Description

Find a structure pool for training by minimizing the correlation between parameters or the condition number of the fit matrix (should be equivalent). There are probably a lot of things that can be improved before merging this, but I start the discussion with some prototype code at least. For me, this has worked wonderful. The idea should be the same as what @erikfransson have proposed in an issue long time ago.

Comments

This method suffers a bit from the fact that you have to choose the cluster space beforehand, and it is somewhat of a slow method.

Additional information

Closes #353 (closed)