MobArena support for Spigot 1.9

[mibby]

Inventory restoring is broken when leaving an arena on spigot 1.9.

[16:23:18] [Server thread/INFO]: mibby issued server command: /ma l
[16:23:18] [Server thread/WARN]: java.lang.IllegalArgumentException: Invalid inventory size; expected 36 or less
[16:23:18] [Server thread/WARN]:    at org.bukkit.craftbukkit.v1_9_R1.inventory.CraftInventory.setContents(CraftInventory.java:65)
[16:23:18] [Server thread/WARN]:    at com.garbagemule.MobArena.util.inventory.InventoryManager.restoreInv(InventoryManager.java:79)
[16:23:18] [Server thread/WARN]:    at com.garbagemule.MobArena.ArenaImpl.restoreInvAndExp(ArenaImpl.java:1012)
[16:23:18] [Server thread/WARN]:    at com.garbagemule.MobArena.ArenaImpl.playerLeave(ArenaImpl.java:662)
[16:23:18] [Server thread/WARN]:    at com.garbagemule.MobArena.commands.user.LeaveCommand.execute(LeaveCommand.java:39)
[16:23:18] [Server thread/WARN]:    at com.garbagemule.MobArena.commands.CommandHandler.onCommand(CommandHandler.java:91)
[16:23:18] [Server thread/WARN]:    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
[16:23:18] [Server thread/WARN]:    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141)
[16:23:18] [Server thread/WARN]:    at org.bukkit.craftbukkit.v1_9_R1.CraftServer.dispatchCommand(CraftServer.java:645)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.PlayerConnection.handleCommand(PlayerConnection.java:1302)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.PlayerConnection.a(PlayerConnection.java:1137)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.PacketPlayInChat.a(PacketPlayInChat.java:45)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.PacketPlayInChat.a(PacketPlayInChat.java:1)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.PlayerConnectionUtils$1.run(SourceFile:13)
[16:23:18] [Server thread/WARN]:    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
[16:23:18] [Server thread/WARN]:    at java.util.concurrent.FutureTask.run(Unknown Source)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.SystemUtils.a(SourceFile:45)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.MinecraftServer.D(MinecraftServer.java:716)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.DedicatedServer.D(DedicatedServer.java:400)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.MinecraftServer.C(MinecraftServer.java:655)
[16:23:18] [Server thread/WARN]:    at net.minecraft.server.v1_9_R1.MinecraftServer.run(MinecraftServer.java:554)
[16:23:18] [Server thread/WARN]:    at java.lang.Thread.run(Unknown Source)
[16:23:18] [Server thread/ERROR]: [MobArena] Failed to restore inventory for player mibby!

[mibby]

Fixed upstream.