Changed some hardcoded offset/alignment for classes in DMD, broke offsets for 64bits. Changed ClassInfo generation to no longer access the default initializer of ClassInfo, fixes problems with index mismatch.

module union2;

union U
{
    float f;
    long l;
}

U u;

void main()
{
    assert(u.f !<>= 0);
    {
        uint* p = 1 + cast(uint*)&u;
        {assert(*p == 0);}
    }
}