Protected/private member variable names sometimes violate C++ standard.

[jdeaton]

As I've been working the last few days I've been using clang-tidy and checking out some of the warnings/errors it gives to see where we can clean things up.

It turns out that an underscore followed by a capital letter is a reserved name in C++ in any scope according to the C++ standard. Incidentally, we use this quite a bit throughout MAST due to the use of an underscore in front of a lot of private/protected member names. For example, _A and _Kappa technically are bad. I like delineating the private members with something, but maybe when we define a style guide we can address this in a future release. We obviously haven't hit any issues, but would probably be good to change anyways at some point.

An underscore followed by a lower case letter is a reserved name at file-level/global scope. I don't believe we have an issue with this anywhere.

• https://en.cppreference.com/w/cpp/keyword
• https://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier