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 typeinfo6;

void main()
{
    auto ti = typeid(int[]);
    assert(ti.toString() == "int[]");
    assert(ti.next() is typeid(int));
}