Update to 1.10 and 1.9.4

• Upgrade to Java 8
• Fix flickering of Bossbar in NEW_BUKKIT_API
• Configurably add 'who' labels to combat tag
• Optionally untag a player if tagged and teleportation is caused by PLUGIN or UNKNOWN to prevent exploits
  • Players can avoid CombatTag by abusing some plugins like NoCheatPlus and WorldBorder since both can cause somewhat frequent UNKNOWN and PLUGIN teleports.
• Set the 'NPC' metadata on the npcs we spawn