Expand World Spawns

v1.17

• Adds experimental drop data support.

v1.16

• Improves the data system to support more types and formats.

v1.15

• Fixes error when set defeated key for a creature was null (for example RTDMMO).

v1.14

• Adds support for data fields to allow customizing creature properties.
• Removes the automatic kill counting system (incompatible with World Advancement Progression mod).

v1.13

• Fixes the global key counting interfering with world modifiers and other key related features.