Fixed weird struct problem from downs, see mini/compile_structs1.d Rewrote DtoIndexStruct/Class , the old implementation were way too complex for what we really need now - since the DotVar changes.

module tangotests.mem2;

void main()
{
    int* ip = new int;
    assert(*ip == 0);
    *ip = 4;
    assert(*ip == 4);
    delete ip;
    assert(ip is null);
}