refs #10530. Use binning boundaries as extents.

Use binning boundaries as extents if they define inner limit. Otherwise the original dimension boundaries are used as extents. In either case, the extents need to be transformed
into the new basis.
refs #10530. Fix extents calculation.

The tests are right, but the implementation is wrong. We should calculate all extents in the new basis first, then figure out the most conservative
of those to use for the actual extents used in BinMD/SliceMD.