Update parameter names in FEModel3D methods for consistency of API

[connorferster]

Hi @JWock82,

I noticed that there were some breaking changes to the API with recent versions but that the updates were not applied to all of the methods in FEModel3D. I have updated the rest of the parameter names across the FEModel3D object by following what seemed to be the desired new convention. Here is how I understand it:

• When creating a new object (e.g. node, member, section, etc.), the method that creates it (e.g. .add_node) will accept a parameter called name to set the name of the object in the model.
• When creating an assignment to an existing object (e.g. a load to a member), then the parameter will be named something like member_name (as opposed to Member) to make it clear that this parameter is to accept a name and not a Member object itself.

I ran the test suite and all tests pass. However, I notice that the test suite does not use any keyword arguments when the methods are called. The tests passing will reflect that the parameter name changes I made in the function signatures have been updated in the function implementations and not that I have followed the naming convention perfectly (although, from manual review, I think I have).

Let me know your thoughts on this?

[connorferster]

Here is an example (from the docs) of what I meant when I referred to changes to the API not being propagated across the FEModel3D methods:

[connorferster]

I also change the Direction parameter to direction but left capitalization in certain parameter names where "FEA conventions" make more sense (e.g. X, Y, Z for global coordinates; E and I instead of e and i (because those are mathematical constants).

[JWock82]

Thanks Connor. I merged your pull request. I've tried to merge my coding style with the PEP8 style guide as much as makes sense for FEA. Some of this is stuff I coded early on when I was still learning PEP8. I appreciate your help. The docs should be updated too.