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 typeinfo5;

void main()
{
    enum E : uint {
        A,B,C
    }
    auto ti = typeid(E);
    assert(ti.next() is typeid(uint));
    assert(ti.init is null);
}