hit a null-pointer exception in the GridArrangement where the block list could be over-run. Fixed this and added a constructor to horizontally align the individual items as desired. The vertical alignment centres the labels, as the CenterArrangement for the blocks does not deal with a fixed width and no height constraint yet. This can easily be fixed if CenterArrangement is updated.
Would be great if this could be included in the next release.
Included is a diff against 1.0.11.