Improved EventHookContainer

Made some changes to EventHookContainer.onWorldLoad() to remove
redundant code that encouraged bugs. Unfortunately, a lot of
link-related code needs to be rewritten to get rid of bugs, so that'll
come after dungeon packs are completed.
Merge pull request #67 from SenseiKiwi/DungeonPacks

Partial Dungeon Pack and Configurable Dungeon Chain Implementation
Merge remote-tracking branch 'upstream/master' into DungeonPacks
Merge branch 'master' into DungeonPacks