Fix VarDecls for tuples. Closes #99. I've implemented it this way since it doesn't require any changes in the frontend. However, I think having TypeTuple expressed as LLVM struct types would make much more sense and open the door to tuple lvalues.

module tangotests.lazy2;

extern(C) int printf(char*, ...);

void main()
{
    lazy1("hello\n");
}

void lazy1(lazy char[] str)
{
    lazy2(str);
}

void lazy2(lazy char[] msg)
{
    printf("%.*s", msg.length, msg.ptr);
}