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.
