Various Oddities

Mainly small-but-significant bug fixes.

• Addressed a bug that caused world crashes when TypesManager was loaded without a world object. Difficult to replicate, expect this one to crop up again sometime.
• Reduced font size of passive abilities on ability menu to improve readability with long-named abilities. As a side-effect there can now be a LOT more passive abilities before running out of vertical screen space.
• Ensured that creature types retrieved are unique, preventing duplicates in some contexts.

Also added spell-effect resistance ability (Immune to Enchantment, Immune to Death, etc.), replacing the handling formerly done exclusively by creature types.

Known bugs:

Abilities remain active on the client until relog even if removed/cleared. This isn't a big problem for activated abilities because the server won't trigger them if the player doesn't have them, but does mean some client-side effects like Blindness remain.