Set world on fixed tile entity to avoid NPE. Addresses BUKKIT-3949

Remapped by Srg2Source from Bukkit/CraftBukkit@eb2d96b9303c9c5ea40bd47704a8b5ac1763d145
Add option to decay flowing lava. Adds MC-4631, #656.

Vanilla has a bug/feature where flowing lava decays
extremely slowly, as in hours/days/never. This change
adds a configuration option to bukkit.yml, which if set
to true (defaults to false for vanilla behavior):

mcpc.flowing-lava-decay: true

will cause a block update to be scheduled after the
random check did not remove the lava, therefore causing
flowing lava to decay at a rate comparable to its normal
flow rate.

For more details see: https://mojang.atlassian.net/browse/MC-4631

This change can be implemented in a mod, however, it requires
either a coremod or jarmod both which are not likely to be
compatible with MCPC+, since CB also edits the BlockFlowing class.
Hence this new config option.
Properly return contents of Inventory. Fixes BUKKIT-3930

When an array of an inventory's contents is requested, we loop through the contents of the NMS inventory's ItemStacks in order to return Bukkit ItemStacks that can be used through the API. However, the NMS ItemStack can, in some cases, be larger tha

With this commit we use the smaller of the two arrays' length as the limit in the loop, thus eliminating the possibility that the smaller array will be asked for an index higher than its length.

Remapped by Srg2Source from Bukkit/CraftBukkit@5bbee6cf1ccc91a705e067d351ada3100832d865