Add 1.8 LivingEntities

This updates the API for 1.8 entities as required for my relative Glowstone PR: https://github.com/GlowstoneMC/Glowstone/pull/282 

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*Edited by turt2live*

**Related links:**
- Glowstone: GlowstoneMC/Glowstone#282
Line too long and implementation details do not belong in JavaDocs