Remove description.py entirely

[toddrjen]

These commits remove the last traces of description.py. All functionality is now moved into the classes themselves, with the except of class_by_name which is moved into neo/core/init.py.

The only functionality that was removed was the name_by_class dict. The same information can be obtained faster and more clearly by changing name_by_class[cls] to cls.name. There are also ways to do class_by_name but they are slightly slower and less clear.

[samuelgarcia]

I would also like something more flexibe for attributes description, using dict and str only.

like thi:

_necessary_attrs = [{'name' : 'time', 'type' : 'quantities', 'ndim' : 1 },
{'name' : 'signal', 'type' : 'numpy', 'ndim' : 3 },
{'name' : 'rec_datetimel', 'type' : 'datetime', },]

I can do the work if you want.

[toddrjen]

I had a similar idea but slightly different details.

However, I am trying to keep the amount of API change in any single pull request and commit smaller in order to make bisecting bugs easier.

So if possible, let's keep the API in the pull request more of a strict refactoring, then we can discuss how to more fundamentally improve the API in a separate issue. Is that okay?

[samuelgarcia]

You are right. The merge is OK me.
Could you open an issue to discuss first on this API ?