nanshe/nanshe/neuron_matplotlib_viewer.py: Change `__date__` to conform to the standard.
nanshe/nanshe/neuron_matplotlib_viewer.py: Change `__date__` to conform to the standard.

DudLab/nanshe,jakirkham/nanshe,nanshe-org/nanshe,jakirkham/nanshe,nanshe-org/nanshe,DudLab/nanshe