this fixes TNT spawning multiple entities when lit by flaming arrows.
The problem here is a bit more complex (entities aren't immediately notified when local block updates happen, so they cache stuff that becomes unusable). The simplest option would be to just lose the cache, but that would have some impacts on performance.
Barring a rethink of the block updating mechanism, this solution seems usable for now.
this new form allows skipping some useless checks during sky light calculation and also allows getting rid of the last hard dependency on core Block classes.
We're getting real close to native light now.
Now, blocks do not respond to silk touch unless specifically opted into. Since this always involves custom drops in one way or another, it's easy enough to figure out which blocks need to be marked for silk touch - anything that overrides getDrops, getDropsForCompatibleTool or getSilkTouchDrops is a block which _might_ need to be flagged. Using these criteria to reduce the number of blocks needing to be checked, I was able to manually invert the behaviour as needed.
This fixes reoccurring bugs with blocks erroneously dropping themselves whenever new blocks are added and someone forgot to set that flag, granting players access to internal blocks with strange behaviour.
