set up skeleton jupyter notebook for a neural feature selection example

[sijia66]

No description provided.

[sijia66]

This is a code example to use lasso feature selection for selecting neural features. Some questions to consider before merging back to the main branch.

1. where to store the test data?
2. SImilar functions in aopy?

[leoscholl]

looks really useful, and seems that you identified some functions that could be added to aopy! i think lasso_main, get_selected_unselected_electrodes and especially plot_electrode_selection would be great additions; please make PRs for those separately when you have time.
i don't think you need to include the test data, that would be better suited to go along with your paper.

[leoscholl]

This looks useful, thanks for removing the test data. I'll make an issue that reminds us to migrate these functions into aopy!