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 nested2;

void func(ref int i)
{
    delegate {
        assert(i == 3);
        i++;
    }();
}

void main()
{
    int i = 3;
    func(i);
    assert(i == 4);
}