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 enum2;

void main()
{
    enum E {
        A,B
    }
    E e = E.B;
    assert(e == E.B);
}