code updated with direct H*v product in the Lanczos channel.
HAMILTONIAN IS NO MORE STORAGE, but for small sectors.

extension: the one before the last step is to
parallelize the code using MPI. The essential
part are already coded, but were commented out.
The MPI version of the direct Matrix-Vector product
must be coded, starting from the available sp_ version.
Merge branch 'devel'