Add Horse API. Adds BUKKIT-4424

API has been added to interface with Horses and to modify their inventories. A new event, HorseJumpEvent, has been added to be fired whenever a horse jumps.

This commit fixes BUKKIT-4393.
Minecraft spec has changed and we're required to follow. We now build with Java 6.
Add API to control scaled health. Adds BUKKIT-4590
Use platform specific line separator to save config files BUKKIT-2368
Cache pattern and clarify constant names
Revert "Cache pattern and clarify constant names"

This reverts commit 03195975eab8a03f69a058145434b543b3abd723.
Revert "Use platform specific line separator to save config files BUKKIT-2368"

This reverts commit 2e2ca8c7b52c88c3255664513c5395824ab6747c.
Use native snakeyaml DumperOptions to format with platform linebreak
Update tests