OpCommands

- Fixes

• The command "/killitems" which no longer existed
• Fixed iron golems and snow golems not spawning on /spawn

- Changes:

• Changed "/killallmobs" command to "/allmobsdie"
• Added selectors for /ng command

- Added the commands:

• /tpdimensions {selector} > teleports players to a dimension
• /speed {selector} > gives speed

- Added parameters to the /troll command:

• charged_creeper > spawns a charged creeper
• sounds > plays a specific sound
• big_jumps > gives levitation
• cobweb > makes cobwebs appear