Add <n@npc.has_pose[<name>]> and <n@npc.get_pose[<name>]>; Fix some tag meta

<n@npc.get_pose[<name>]> returns a defaulted dLocation where x, y, and z
are 0 and the world is the first world Bukkit gives us.
Add "update" to Inventory command

At the moment, only player inventories can be "updated", but it's a
needed feature.
Update Pose command to 0.9, add some new options

You can now add and remove NPC poses.
This also stopped a few NPEs, such as the player being the target and it
never checking if an NPC exists... When an NPC HAS to exist.
Fix error in dLocation constructor

I have no idea how long this has been here, or what kind of trouble it's
made.
Merge pull request #556 from Morphan1/master

Second best pull request ever