Support for MCPatcher's "Random Mobs" and OptiFine's "Random Entities"

[NatoBoram]

• Basically Support for MCPatcher's "Random Mobs" and OptiFine's "Random Entities" variedMobs#18

I think there would be more demand for compatibility with previous formats before new formats are necessary. For example, I want to use Alternate Entities, but it's not really possible at the moment.

• MCPatcher's "Random Mobs"
• OptiFine's "Random Entities"

I imagine it's a non-goal for this lib, too?

[Digifox03]

The purpose of this library is to provide a replacement format, not to use the previous ones.
If there will be a way to provide compatibility, it will be part of Varied Mob Textures, a conversion tool, or a standalone mod.