Added ralph src for a test that we can wrap endpoints in structs.  It currently fails with a compile error.
Previously, could not have a struct with an endpoint in it.  This was
because building struct definitions happened before we resolved
aliases for endpoints.  This commit tries to solve that by adding
endpoint objects to fixup lists.  This is pretty ugly code.
Calls of the form

Struct A
{
    Endpoint B b;
}

Struct A a;

a.b.do_something();

fail.  Must actually separate into:

Struct A a;
Endpoint B b = a.b;
b.do_something();

Filing an issue on github.