dax::Extent now is properly aligned based on id size.

Previously we aligned dax::Extent based on scalar size which was wrong, since
it only contains dax::Ids.
Stopped aligning the uniform topology since in mixed 32/64 it was too hard.

When mixing 64bit id's and 32 scalars it is hard to determine the best
alignment, so lets skip even trying.
Merge branch '64bit_id_warnings'