Add, change, delete servers.

For add, change or delete name and paths of servers, just select the servers then if you want to:

• add: just write the new name and select the new path (select the PocketMine-MP.phar for choose its)
• change: just write the new name (if empty will be "Server_Minecraft_PE_{position}") and select the path to change.
• delete: just select the server.