Player reported that animals would not breed in an area with PREVENT_SPAWN flag set to true.

To remedy this I have split PREVENT_SPAWN into different categories

Added flags:
PREVENT_SPAWNER_EGG
PREVENT_BREEDING
PREVENT_BUILD_IRON_GOLEM
PREVENT_BUILD_SNOWMAN

Removed breeding, spawner egg , building iron golems and building snowmen from PREVENT_SPAWN flag.

PREVENT_SPAWN will be used for any other spawn events.