bug: hopper upgrades do not always save correctly

[nkomarn]

It appears that chunk borders may have something to do with this; some players have reported that their hopper upgrade tiers do not always save the correct value, or just roll back to the default tier.

[nkomarn]

This has been brought up again (see ticket #110), so there's definitely something going on behind the scenes. The patch for hopper upgrades has not changed in quite a few game versions but the issue is fairly recent, so it's likely something was changed when it comes to block entity saving at some point in time.