use static OpenMP scheduling to allow cache fusion

although I am not sure if this applies along function calls,
especially as we use nowait clause, there is no guarantee (?)
that decomposition is the same. Also, use dynamic/guided might
be more effective in hand with nowait.
minor polishing and fixes
critical bug fix for non-linear runs with threads

Critical bug fixes which invalides all previous results, which
included electrostatic runs, including the non-linear terms with
at least 2 OpenMP threads.