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 globals2;

template Bool(bool b)
{
    const bool Bool = b;
}

void main()
{
    assert(Bool!(true));
    assert(!Bool!(false));
}