Bugfix: The parameters, which are fixed by the EWSB eqs., have to be
defined at the susy scale (at the one-loop level)
Bugfix: When we call solve_ewsb_tree_level() we overwrite Mu and
BMu.  So, we have to restore them!  This restoring is not necessary
at the high and at the susy scale, because at the high scale we do
not call solve_ewsb_tree_level(), and at the susy scale we call
at the end solve_ewsb_one_loop().