Avoid calls to unwrap_Val() when interpreting Tul code
Remove obsoleted C++ code (unwrap_* functions)
Remove obsoleted C++ code (struct V_Addr and V_Type_Addr)
Remove obsoleted C++ code (struct V_Type_FuncDecl and V_Type_TypeDecl)
Remove obsoleted C++ code (struct V_Type_IntConst and V_Type_FloatConst)