I.e. nT x nVec eigenvalues are saved in FileName.evals.conf.h5.
A new named tensor, "TimesliceEvals" can be used to simplify restoring these from disk.
NB: The changes in BaseIO add support so that Eigen tensors can be easily used in MPI operations, e.g. GlobalSum.
See LapEvec.hpp for an example of how this is done.