[MRG] Make methods/attributes private

[ntolley]

Closes #448

@michaeldeistler @jnsbck is the list of methods/attributes to make private actually agreed upon? Here's what was stated int he issue:

"par_inds",
"child_inds",
"child_belongs_to_branchpoint",
"solve_indexer",
"cells_list",
"cumsum_nbranchpoints_per_cell",
"cumsum_nbranches"

I've started with par_inds to get a feel for the code base, but I'll wait for you input before continuing

[michaeldeistler]

Hi Nick! Great that you are getting into Jaxley!

And yes, the list is agreed upon. Thanks for tackling it, let us know if anything is unclear!

Michael

[ntolley]

Definitely happy to help out! Super cool project that I think will be great for my research questions

I think I've covered all the attributes so this is ready for review

[michaeldeistler]

Awesome! Automated tests are failing right now because of black. Could you run:

black jaxley
black tests

Thanks a ton!

[jnsbck]

Hey! Welcome on board also from my side! :) Cool to have you also working on Jaxley. Feel free to reach out at any time if you have questions or ideas :)

[michaeldeistler]

Tests are passing, and all looks good now! Thanks @ntolley!