Tidying up: grad_norm and test_out_files
FideliyComputer.norm_grad_sq_sum renamed to grad_norm
also now calculted as sqrt(sum(grad**2)),
as this seems to be what the L-BFGS-B uses as a norm
Replaced test_out_files (integer) attribute with specific (Boolean) attributes
for outputting various (7) kinds of test output files.
4 new kinds added. See OptimConfig class for descriptions.
Improved formatting of test out files
remove: initial fidelity error and gradient calculated during dynamics.initialise_controls
        caused errors when using unitary dynamics