The copy.deepcopy() function is now used for all numpy input data to avoid the data from being
modified between function calls. This is important for missing RDC and PCS data which is sent in as
NaN values. In the target function __init__() method, the NaN values are replaced by 0.0 after the
self.missing_rdc and self.missing_pcs structures have been by checking for NaN values. However the
recent specific_analyses.frame_order.optimisation change in the Frame_order_minimise_command slave
command to printout the number of integration points resulted in the target function being
initialised twice, causing all NaN values to be 0.0 in the second initialisation. Hence all missing
data was being treated as real data with values of 0.0.
