Small additions and bugfixes

Container: Added size limitations to containers, you can limit the
capacity for specific sized items inside containers with new parameters
on CreateContainer. To check if an item type will fit into a container,
a new function WillItemFitInContainer has been added. Similar functions
to Inventory.pwn have been added to properly control extra options to
container items.

Item: Added a callback called OnItemNameRender called whenever a
specific item's name is requested by a script, this allows the use of
SetItemExtraText within this callback in order to add extra information
to item type names that is specific to that unique item. Also added a
new function GetItemName, this differs from GetItemTypeName as it
returns the item's type name and the item's unique specific text it is
assigned with SetItemExtraText in brackets.

Inventory and Container have been updated to use the new GetItemName
function.