Updating `MDAtom` class.
Updating `MDAtom` class.

Adding the `t0_atom` attribute to the `todict` dict
and `__dir__` list and updating the `NN.setter`
method code to improve readability.

scikit-nano/scikit-nano,androomerrill/scikit-nano,scikit-nano/scikit-nano,androomerrill/scikit-nano