GitLab

Note: Also in this commit:

1. Changed test values in NiO_ldauXML test since now the broyden files get deleted
   when a new density matrix is generated
2. The NiO_ldau test should not work any more since linear mixing for the density
   matrix is removed for the old inp file. (It is not specified in the n_mmp_mat
   file any more)

Note: The NiO_ldau and NiO_ldauXML tests had to be adapted to this new
behavior of the code. The new behavior is reasonable.

Also slightly cleaned up test NiO_ldau.