Draft of fixes needed for supporting variadic templates

[anstadnik]

Hi, this pull request is a draft regarding #109.
So far it compiles and works when used with the variadic template, but it has some problems.
In particular, the problem occurs here. I haven't yet came up with a solution on how to separate variadic packs from the actual arguments. My guess would be to try to change this to something like:

#define dbg(...)                                    \
  DBG_MAP(dbg::DebugOutput(__FILE__, __LINE__, __func__)    \
      .print(DBG_STRINGIFY(__VA_ARGS__), __VA_ARGS__))

This way it will call the print separately for each argument, and in my head it looks somewhat similar to

template <typename... T>
void test(T&& ...args) {
  dbg('v', args..., 1);
};

int main(void)
{
  test(v, 1);
  return 0;
}

converting to

dbg::DebugOutput("potato.cpp", 42, "test")    \
      .print("v", 'v'), \
dbg::DebugOutput("potato.cpp", 42, "test")    \
      .print("args...", args...), \
dbg::DebugOutput("potato.cpp", 42, "test")    \
      .print("1", 1)

, and after that it will be processed accordingly in the print function.
It will require creating a DBG_MAP function for 2 arguments, but will make print function much easier, and will remove the need in hacks with initializer_list.

[anstadnik]

Seems that I didn't really understand why you used a macro for getting types of variables. This change breaks it as it doesn't preserve the true type of the original variable, and instead outputs the type inside of a function.