Added missing import of ProjectorGroup and ProjectorShell to
'plotools.py'.
Moved separate routines 'orthogonalize_projector_matrix()'
and 'select_bands()' into class ProjectorGroup because these
routines are anyway not used elsewhere outside this class.
At the moment the file have just been copied from 'c_plocar_io.c'
and most of the old functionality is commented out. Eventually, this
should become a parser of PROJCAR, LOCPROJ written in C for greater
performance on large files.
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.
