Some arrays had to be deallocated before allocating them (again).

1. Now the inverse of the Hessian is invers to the Hessian
2. Added the Lagrange multiplier to dEdOcc

...still in construction and with a lot of debugging output.

specify -DCPP_OLDINTEL to deactivate parts of the code that did
not compile; mainly the order of USE statements was changed or
ONLY was added to avoid confusion of the compiler.

The preconditioner already improves the convergence of Cu and Fe files, but the starting distance is higher than for the older fleur version and tests run up to test 7 only (does not fail, but hangs).

At the moment this variable is without function. Later it will be used as a switch between the Yukawa and Coulomb cases in the potential generation.
Since the preconditioning parameter is now stored in the input file and since both the Coulomb and Yukawa potentials are generated in a calculation with preconditioner, the switch cannot simply be based on the value of the preconditioning parameter. This is quite ugly and we might want to change this somehow later.