Improved pretty

[apdavison]

No description provided.

[JuliaSprenger]

Hi @apdavison These pretty representations are only used by the ipython lib or is there any way on how these are used by python itself? What is the advantage of having this verbose representation instead of the __repr__ implementation?

[apdavison]

Yes, these are used in IPython and Jupyter notebooks. Python also has the pprint module. This PR is basically just improving the "pretty" representations for Epoch, Event and SpikeTrain; the representations for AnalogSignal, Segment, Block are already ok.

[JuliaSprenger]

For me the Python pprint is not using the _repr_pretty_, but _repr_. Did you expect pprint to also use the new implementation?

[apdavison]

I wasn't sure about pprint, but I didn't test because I was mainly concerned about IPython and Jupyter.

It would be good to refactor things in the future to have consistent behaviour between _repr_pretty_ and _repr_, but for now I just want to be sure that IPython pretty gives consistent behaviour across the Neo core classes.