`return_raw_data` should include all timings (for `n_repeats`)

[DanielHabenicht]

It would be nice if all of the raw data could be passed back if requested instead of only the minimum (for executions with n_repeats>1)

big_O/big_o/big_o.py

Line 61 in d700425

execution_time[i] = np.min(measurements)

So one could calculate standard deviation for the runs or perform other actions with it.

While at it it might be good idea to pass the raw data back in an extra variable instead adding it to the fitted dictionary:

big_O/big_o/big_o.py

Lines 171 to 175 in d700425

	if return_raw_data:
	fitted['measures'] = ns
	fitted['times'] = time
	return best, fitted

Idea:

return_values = (best, fitted)
if return_raw_data:
    return_values = (best, fitted, {
         'measures' = ns,
         'times' = time
    })
return return_values

Happy to provide a PR!