Simplification of the field access macros

[llaniewski]

The field access macros (both develop and unstable) can be greatly simplified using the design below:

template <int x = 0, int y = 0> void fun() {
    printf("static x:%d static y:%d\n", x, y);
}

template <int y = 0> void fun(int x) {
    printf("dynamic x:%d static y:%d\n", x, y);
}

void fun(int x, int y) {
    printf("dynamic x:%d dynamic y:%d\n", x, y);
}

#define fun_static(...) fun<__VA_ARGS__>()
#define fun_dynamic(...) fun(__VA_ARGS__)

Notes

I investigated compiler level discovery of static/dynamic value, and no solutions (even C++2a) were viable. The current user-level choice between f1(0,0) and f1_dyn(dx,dy), will be kept.

[llaniewski]

Mostly done by #440