There was an inconsistency in the convention on the position of the
subarray corresponding to projectors within the selected window.
In some cases the subarray was defined from 0 to ib_max, in other cases
it was from 'ib1 - ib_min' to 'ib2 - ib_min'.
Now the global convention is that the projectors for a given window
are stored in a slice '0:ib_max', where 'ib_max = ib2 - ib1 + 1'.
There was a mess with indices 'ib_min', 'ib_max' indicating the
selected window. First of all their old names 'nb_min', 'nb_max' were
confusing and because of that they were sometimes incorrectly used as
the maximum size of the window and sometimes as a maximum band index.
Now the convention is more clear: 'ib_min', 'ib_max' correspond to the
minimum/maximum band indices (in terms of original VASP indices) and
'nb_max == ib_max - ib_min + 1' is the maximum number of bands within
the window.
Added output of density and overlap matrices to plotools.py.
If one defines a very large window (spanning all bands) one can
compare this output with the one produced by 'debug_density_matrix()'
in class ElectronicStructure.
For a small window, the overlap gives an idea of symmetry-related
degeneracies and of how strong the states are going to be renormalized
by the orthogonalization routine.
The new projector input requires a different approach of selecting
the projectors for each shell. Specifically, for each site/orbital
index defined for a given shell one has to look for the corresponding
input projector (from PROJCAR).
Also, small fixes were required to make 'ferw' array index order
consistent with what is expected in ProjectorShell. This order might
eventually be modified.
Since in the new implementation the projectors produced by VASP
are output only for selected functions it is necessary to check
that input cfg-file specifies only those projectors that were selected
in the INCAR file. The consistency routine checks for every shell
and site/orbital character that a corresponding projector is present
in PROJCAR.
The files from the original vasp-interface repository are reshuffled in
accord with the directory structure of dft_tools. Some of the directories,
such as 'test' (unit tests for the interface), 'examples' (simple examples for
the development purposes) are temporarily placed into 'python/vasp' directory
to avoid confusion with integral tests and examples of dft_tools.
