Added racecourse type and mount data registry
- Adds configurable custom mount data eg. horse colour/style/variant (NB. data classes for all entities with custom data will need to be written)
- Adds custom racecourse types
Merge branch 'master' of https://github.com/CodingBadgers/MineKart

Conflicts:
	src/main/java/uk/thecodingbadgers/minekart/jockey/Jockey.java
	src/main/java/uk/thecodingbadgers/minekart/racecourse/Racecourse.java