Prevent ConstraintFragmentSampler to always set cst_weight to default value if not specified by user.
Cst_weight is now only set, if indicated by user (and thus not overwriting atom_pair_constraint patches).
Expected Integration Test Changes (Overall Score is identical, only the atom_pair_constraints=0 entries are removed):
broker
ThreadingInputter
broker_membrane
fold_and_dock
metalloprotein_broker