inventory overhaul!

- inventory.java is defunct now, entities handle their own inventories
now
- new: entity removal
- new: entity inventory loading
-> will likely allow for template entity loading later on
- new: entity writing
-> entity attributes currently: id, name, coords
-> current hold health and inventory, will probably be expanded upon
later
- partial parser overhaul to come
-> need to make commands like "give" and "delete/remove" target entities
in the game
-> need to add support for seeing entities in the same room too, drop
support, etc so that you can 'admin remove item from someNPC'
- added getChildren to XMLReader
-> to be honest, XMLReader will likely be completely redone in the
future, its a mess right now
- added writeTextContent to XMLWriter
-> used in loading entities in from an entities inventory
-> THERE IS NO HARD LIMIT ON HOW MANY INVENTORIES CAN BE IN AN
INVENTORY. be wary
-> also while there is a check for having an entity not load itself, if
two entities contain each other they'll probably break the game. will
likely add an ID check later on to make sure that you can't do this