Interpret world seed as number if possible (fixes #427).
Fetch UUIDs from Mojang if needed (fixes #227, fixes #365).

UUIDs are only fetched if online mode or proxy support is enabled.
Additionally fixes problems when player data files are missing a last
known username.
Fixed or added several broken inventories.

Added GlowInventory#getRawSlots() to handle a protocol special case.
Changed TEContainer to take an inventory rather than an inventory type.
Adds or fixes enchantment tables, anvils, brewing stands, furnaces,
workbenches, dispensers, droppers, and hoppers.