PMMP closes without any error

[inxomnyaa]

Issue description

Steps to reproduce the issue

1. Start pmmp
2. well, over all it seems like to happen instantly with plugins, and delayed without.

OS and versions

• PocketMine-MP: i can't execute the command. 'Latest'
• PHP: 7.0.9
• Server OS: Windows server 2012 r2 x64

Crashdump, backtrace or other files

• Nothing. Nothing in log, nothing in debug.

[inxomnyaa]

[10:14:28] [Server thread/INFO]: Fertig! (1.775s)! Für Hilfe, tippe "help" oder "?"
[10:14:28] [Server thread/CRITICAL]: Exception: "FORCED" (EXCEPTION) in "/src/pocketmine/Server" at line 1879
[10:14:28] [Server thread/DEBUG]: #0 /src/pocketmine/Server(1600): pocketmine\Server->start(boolean)
[10:14:28] [Server thread/DEBUG]: #1 /src/pocketmine/PocketMine(492): pocketmine\Server->__construct(pocketmine\CompatibleClassLoader object, pocketmine\utils\MainLogger object, string C:\Users\Administrator\Desktop\Server\MinecraftPE\WolvesFortressCSphp7\, string C:\Users\Administrator\Desktop\Server\MinecraftPE\WolvesFortressCSphp7\, string C:\Users\Administrator\Desktop\Server\MinecraftPE\WolvesFortressCSphp7\plugins\)
[10:14:28] [Server thread/INFO]: Stopping other threads
[10:14:28] [Server thread/DEBUG]: Stopping Console thread

Added an exception throw in the function 'forceShutdown'

[dktapps]

That's a very strange backtrace. Hard to say what could cause that.

[inxomnyaa]

Turns out it appeared on the plugin signshop causing an error and somehow shutting down the server

[dktapps]

For reference: https://github.com/NikoZazza/SignShop/issues/24

I think this merits plugin permissions if this could be implemented, to prevent plugins abusing things like Server->shutdown() and causing issues like this.

[inxomnyaa]

& removing files outside the plugin folder. You could wipe the whole plugins folder, and maybe also the whole server with just one sneaky plugin

[dktapps]

Some quality control is definitely warranted I think.